One piece I added for this trip was a mid-weight down jacket, which I wore extensively on the lower mountain (14,000 feet and lower). Another I wore a lot on the lower mountain was a light hooded fleece. The whole time we were climbing from base camp to 14,000 I wore this fleece over a quarter-zip base layer. This gave me a good "system" to accommodate changes in the sun/wind, as well as exertion level. Starting from camp, I could go in the warmest configuration- hood up, fully zipped, sleeves tucked into gloves. As I warmed up for whatever reason, I could unzip a little, to all the way when it was really warm. I could lower the hood when I was warm, and put it back up if the wind started blowing or it cooled for any reason. My last relief valve before having to take off the fleece was to pull up the sleeves a little. Another part of my system was a buff, which can provide sun and wind protection. I used it largely for its UV protection, pulling it over part of my face, my ears, and ball cap. This gave warmth in addition to a hood, or just by itself. The material is light and breathable, so it didn't get too hot often, but when it did I could slide it down to my neck. This, however, left my ears exposed to the sun. The baseball cap, an RMI one given to us as part of a goodie package, I wore almost every minute I was outside. Because of the intense sun and sweating, the bright red color quickly faded to something of a light pink.
I wore a pair of soft-shell climbing pants nearly 24/7; some warmer nights I took them off to sleep, and a couple of times I put on insulated pants in camp, but just to air out the climbing pants outside. When I put them on at 11,000, I soon opened the vents all the way, they were so hot. The only time I really wore the "puffy pants" was on summit day (in addition to climbing pants and long johns). It was so cold that morning, and all the way to the top, I really needed them. It was warmer coming down, I probably could have taken them off at some point, but I was not in a mental state at that time to really worry about thermal regulation. I had three pairs of synthetic underwear, and changed them at the major camps. I wore a pair of micro-weight long johns at 14,000 camp. Not so much because it was cold, more because I put them on and didn't feel the need to take them off. The only time I really wish I didn't have them on was coming back from caching at Washburn's Thumb and it was broiling hot below the fixed lines. I wore a mid-weight pair of long johns on summit day. Let's just say this region of my body didn't exactly smell of roses most of the trip.
My heavy parka was used on the lower mountain mainly as a pillow, and to put on during breaks on carry days (on move days on the lower mountain, I put on my lighter down jacket, I didn't bring that one on carry days, only the heavy down as storm kit). On the upper mountain I wore the heavy parka more often. I wore it almost any time I was outside at 17 camp. I wore it climbing from Washburn's Thumb all the way to the summit and back to 17 camp. I honestly don't remember when (or if) I took it off coming down from 17 to 11. My mid-weight down jacket (aka "light puffy") was sort of a "go-to." I wore it around camp on the lower mountain when it wasn't brutally hot, I sometimes wore it climbing (again when it wasn't too hot), and I usually brought it with me to dinner in case it got cold while we were sitting around. My soft shell jacket was used the least. Other than putting it on in camp just to say I wore it, I wore it for the first stretch on the move from 14 to 17 (at which point I reconfigured my layers) and on summit day. I wore every layer I had with me on summit day: base layer, light fleece, soft shell, light puffy, big puffy. Basically, since it didn't have a hood, it wasn't nearly as useful to me as the other layers. I actually kind of wanted to get a picture of that jacket on the summit, since it's an Ironman Texas finisher's jacket, but it was much too cold.
My boots were the same La Sportiva Spantiks I used in February on Rainier. This trip was the first time I used my orthotics in them, which may be why they felt too narrow for the first couple of days. After that, they were pretty comfortable (until the descent) and plenty warm. Either the heat molding feature kicked in, things settled out, or I just got numb to the pressure, I couldn't say for sure why the fit was better. Other than Pete and Derek (who both wore Scarpa), everyone on the trip work La Sportivas, with the Baruntse being the most popular, and two pairs each of the Spantik and Olympus Mons. I brought four pairs of mid-weight hiking socks, three pairs of liner socks, and one pair of heavy socks. I was planning to wear the heavy socks on summit day, but was advised against it, as they can cause pressure and have the opposite effect, making the feet colder; I wore them to bed at high camp. I rotated the socks out every few days. The first few days, when it was warm at night, I took them off to dry out while sleeping. At 11,000 and higher, I generally left the same pair on for a few days straight, then swapped to another pair before we moved again. I don't know that the liner socks really did anything for me; I still had some blistering, but not bad; mid-weight socks should be plenty of warmth with the boots I have. One of the least used items, certainly the highest weight-to-usefulness ratio, was a pair of neoprene overboots. They were only worn on summit day, and have a bit of weight to them. Not only that, but they catch crampons easily and get nicked up quite a bit; it's no wonder they aren't available for rent. There were several options for footwear around camp. Some favored down booties (I only wore my pair at 11,000, where they got wet, and I cached them there), others their boot liners. I generally just wore my boots loosely, though for short trips I did wear just the outer boots. Below 11 camp, I did walk around in my boot liners, but the guides discouraged this as the liners have almost no traction, and it can get icy in camp. At least one person got a little more use out of their overboots by wearing them around camp.
When we were first playing with our crampons at 11 camp, Pete had me adjust mine so there was less sticking out the front. It was not intentional on my part, but apparently the way they were set up would be better for ice climbing than walking, and since we weren't really ice climbing (although the fixed lines sometimes felt like it), I adjusted them. There are a lot of little things needed over and above a trip like Rainier: non-locking carabiners for various rigging, a second locking carabiner for the sled, cord and bungees for the sled, prusik loops for emergency use, a mechanical ascender (aka a jumar), slings for an ice axe leash and for the ascender. The jumar is probably the least used piece of gear: barring an emergency, it's only used on the fixed lines, and only while going up (other than the guides using one as a backup on the descent). Even still, it's kind of a fun piece. Since it's got little teeth to bite onto the rope, you can put weight on it, which allows you to just sit back and save energy when the rope team stops for an anchor. The least technical of the specialized gear was the sled. Apparently somebody makes a slick, high-tech sled, but according to those who would know, the best option is a basic plastic child's sled. Some cord is added for towing and rigging, but it's pretty much the same thing you buy for $10 when it snows; there are piles of them at base camp. As a group, we carried several collapsible aluminum shovels, used for
[Ed: I thought of a few more things to note after this was originally posted]
My sleeping bag was rated to -30; we all had two sleeping pads, a closed-cell foam one and an inflatable one; together this kept me warm the whole time (although often wearing some clothes to bed), and not too hot.
The clothing items I really wish I had brought were town clothes. I'm not sure why I didn't bring any, probably I just packed for the climb. I did have a pair of shorts at least; after being on ice weather in the 70s was plenty warm to be walking around in shorts. I bought a couple of t-shirts in town, and I hand washed a pair of underwear, and that was enough to get me home. The other thing I picked up in town was a pair of flip-flops to relieve pressure from my smashed toes; once I put them on, I didn't wear shoes until I got home.