I was in Antarctica for 2 months in year 2016 to launch and support the ANITA-4 mission. I was mostly at/near McMurdo (MCM) Station. 

What to pack (thanks to Steph Wissel, Brian Hill for heavily contributing to below list):

(You will be issued Extreme Cold Weather (ECW) gear at the USAP CDC in New Zealand.)

-- TISSUES. If you use tissues to blow your nose, bring 'em. There are none on that continent but you WILL make insane amounts of nasal mucus. 

-- Plenty of normal street clothes, like what you wear everyday here. In MCM you can do laundry once a week, but if you are traveling to field camps probably not as often. 

-- Several leggings for wearing under clothes as needed. There were days when I wore JUST warm leggings for pants and I usually regretted not layering up more. 

-- Couple pairs of thermal underwear (e.g. from Cabela's) for when staying out for longer periods of time. Definitely for hikes. Remember, if it is nice in MCM doesnt mean it will be nice everywhere and weather in a desert can CHANGE very quickly and drastically.

-- Long thick socks (Costco has good deals) 

-- At least one warm hat, preferably one that preserves body heat (e.g. from Cabela's) 

-- Earplugs, noise canceling headphones (to mitigate military plane LOUD noise, room-mate's snoring, loud talking, etc.)

-- Good Eye mask in case your roommate's schedule is different from yours, plus remember 24-hrs sunlight during Summer there 

-- Slippers for going to the bathroom.  Some dorms have community bathrooms. Others share bathrooms between two suites. 

-- Workout clothes and shoes. There are 2-3 gyms in MCM. 

-- Warm Slippers for wearing in dorm, common room. I also wore a warm fuzzy house-gown a lot in the dorm and everyone else wished they had one. 

-- Work gloves that you can grab screws with. Good to have these in addition to the gloves you will be issued. Throw in some hand-warmers if needed. You get hand-warmers in MCM. 

-- Decent-ish sunglasses, few pairs.  You don't want really cheap ones since you really rely on them. They might break so you might want a few. I bought one $100 Michael Kors pair that lasted me the whole season. 

— Spare prescription glasses, contact lenses 

— Washcloth and towel

— Sandals for the shower as they are dorm style

— Good Body Lotion, it is VERY dry there

— Power adapter for your time in New Zealand

— Lightweight boots or decent shoes for hiking and wearing around McMurdo. The hikes are over snow, gravel and rocks, you don't need anything extravagant but you probably want decent shoes.

— Some sort of music player, book, or something to keep you busy during the 45 min rides to and from LDB (for ANITA). NO internet on your phone there. 

-- Nice Clothes for holiday dinners (Christmas, Thanksgiving) 

-- Good camera 

— Backup harddrive (at least 1-2TB) 

— If you have space, backup laptop.

-- Medicines. Lots and lots of cold meds, pain-relief type meds, digestion/diarrhea meds, general first-aid kit stuff is nice to have. You can get some meds there too but bring your own supply. 

— Any arts and crafts supplies or games, etc. you really want to have. You can check out musical instruments and ski equipment from the station. There is an arts and crafts room. Games are available in the wine bar. There are two gyms, one with aerobic machines and another with weights. There are also yoga classes and a knitting community.

— For television, there are VHS and DVD players in the lounge. There is a TV in grantee's rooms that plays movies regularly. I brought a 256GB flashdrive full of movies and shows. 

— Party clothes. There are several dance parties throughout the summer season. There's also a costume party on Halloween, but people just usually go to Skua (a place where people get rid of stuff and others pick it up for free.

-- Wipes for cleaning hands, etc. on the plane or in a field camp. Military plane bathrooms are very interesting and may not have the stuff you are used to. 

— Some people buy whiskey in Christchurch at this whisky wholesaler and then they have a nice bottle for the entire season. You can bring liquor in your luggage if it meets the weight restrictions.

Tips about getting ready for the flight from Christchurch:

— Most importantly, when you check in for your flight, you should assume that your bag is going to be taken away from you and you won’t get it back for a few days. So pack a change of clothes, shoes, underwear, and grooming supplies in your carryon. 

— The CDC gives you orange bags to pack your ECW into. You can expand your carryon to accommodate your backpack and shoes that way.

— Make sure to use the restroom on the plane well before you land in Antarctica. You won’t be able to use the restroom for at least an hour or two after you land, because you have to ride from Pegasus to McMurdo on a slow moving people mover (say hello to Shuttle Bob for me, I miss him terribly).

Brian Hill's advice collected by Steph/Oindree:

You will be issued a lot of gear at the clothing distribution center (CDC) in Christchurch. My advice to you is to take everything. You will be given an opportunity to try things on, so try everything on.

I would recommend making the following changes:

-Swap the bunny boots to Baffin boots or if you can't get Baffin boots, switch to FDX boots.

-Make sure you get little red, it's like a windbreaker but with a lot of pockets. I normally wore pants or shorts, a t-shirt and maybe little red. If it was cold, I could wear another layer under little red.

-If you are going to spend any time in the field, ask for gauntlet gloves. I found it really nice to throw a bunch of handwarmers in the gauntlet gloves so I could do whatever fine work I needed to and then put  the gauntlets on to warm up my hands.

-I would swap the windpants they issue you for Carhartts. 

If they give you a hard time tell them you are a grantee and will be in the field. I will turn most of the stuff back in because I don't need it, but it's better to find that out through your own experience.

There is a library there with books, DVDs are available at no charge, there is a gym, they have an ATM, a limited selection of toiletries are available but they have everything soap, shampoo, conditioner, toothpaste, lotion, deodorant... Food is free, alcohol is available for purchase in at least the bars and probably the store. There is a gift shop in McMurdo and at the New Zealand base, Scott Base.

Here is a shot of the gear that can be issued. Not all of it is issued to you, some of it you have to ask for.

http://2.bp.blogspot.com/_th9f3B97Gno/TQcLMjUCHoI/AAAAAAAAAyo/-VfzNvCWrPY/s1600/IMG_2624.JPG

I'll point out a few things, the boots are on the right. It's hard to see, the top are Baffins, the middle are FDXs, the bottom are bunny boots which are the default. Most people don't like them, but some do. I think it's worth switching to something else and if you really don't like what you got, blame me.

The gauntlet gloves are green and just to the left of the FDX boots.

All the items I suggested swapping for are available or were available from the CDC.

You must get the boots, big red, carhartts or windpants, and goggles. They also issue you little red, a fleece jacket, fleece pants, thermal underwear, socks, multiple gloves, mittens, glove liners, a balaclava and maybe a neck gator. If you are familiar with cold weather, we shouldn't see much below about -30F,  and you have your own gear, I would say bring your own. I would plan on doing a one for one swap so for example if you have a fleece jacket, or a good midlayer, I would say forgo the one from the CDC and bring your own. However, Christian has a lot of his own gear, but I think he will be leaving it here because he doesn't want to lug it around with him.

Yes you can mail things from McMurdo, that includes postcards, letters, and packages. Because of the weight restrictions a lot of people mail gifts back. They have postcards and stamps available for purchase there.