Pretty common question. One, in fact, I was asking myself many a time. It was about two years ago to date that I was throwing my life into an oversized suitcase (seriously, one of those massive ones on wheels), a duffel bag, and a backpack before heading to Oman for three months. But after living there for awhile, I realized I overpacked. Some of the clothes I packed I never wore and others I wore a couple times a week. Turns out, contrary to the packing list, we didn't need entirely nice and formal clothes all the time; just presentable clothes (the packing list said the Omanis dressed 'formally'). I didn't need to pack all the toiletries for the three months as there was a corner store a block from my family's house, and a Carrefour (Wal-Mart like store) and Hypermarkets all around the area. I even remember one girl in my group who brought a printer! Whew! So what I learned from that is a) take packing lists lightly, b) you can buy anything you need in country.
When thinking about packing for the Peace Corps, the question is 'How do I pack for two years?'. But really, I think, it's the wrong question. Think about packing for three months, or even shorter. Maybe even a month. People bathe, wear clothing, wear shoes, write, etc in whatever country you will be working at. So things like soap and toiletries, just pack/case/bottle of each. For the most part, in most other countries, people try to look neat and presentable. That doesn't mean formal business clothes all the time. Usually that means pants (depending on where/the situation, jeans might work, but they can be a pain to wash/dry) instead of shorts, and either a button down t-shirt or long sleeve button down. It's hard to say until you're actually there.
As for shopping: most PC'ers are going to visit REI or Cabella's at one point I imagine. I would start making a list of things you need that you don't have, especially high-end or things you can't pick up at a thrift store: boots, sleeping bag, pack, etc. Search online for REI alternatives, such as backcountry.com, sierratradingpost, campsaver.com, etc. These sites are typically cheaper than REI or other similar stores. But shop as early as possible, so you can take advantage of free shipping and be able to return items if needed. I also learned that REI is pretty cool about letting you try stuff out, so if you don't know what type of sleeping bag you want or what size boot/Chaco to order, check it out at REI. And on the other side, sometimes you just won't find a better price unless you find a sale (such as with backpacks).
Saying all of this, I know I overpacked. Namely, I took a few too many shirts, but ones that will remind me of home. I took the Doink shirt, the Sidney Crosby shirt, and the Wooster Pipeband shirt, plus my favorite plaid/flannel shirt. While these shirts will definitely make me stick out as a foreigner, my six foot+, floppy blonde/brown hair really don't help the cause either. And then again, These will be good mementos for when I'm homesick, or something to tell people about as they all represent a different part of my life.
I think what might be worth noting is what I'm NOT taking:
-long underwear (never worn them even in the coldest of winters, why would I start wearing them all of a sudden?)
-suit jacket: I can get one in Peru as needed, and it looks like the volunteers swear-in wearing PC track suits (?)
-Most OTC medications since they're available in Peru and provided by the PC
-Fannypack/moneybelt: see long underwear, never used it in Europe or Oman
-Food: I can get it shipped down later and there will be plenty to eat once I arrive!
Below is a list of what I'm taking. However, this actually means very little as I still have no idea of what I actually need, or what is useless.
So here's what I'm taking:
(Here's all three bags packed. The two main ones weigh about 50lbs, half as much allotted by the PC)
Osprey Atmos 50L bag (I originally ordered the 65L and actually thought it would be unnecessarily large, and the 50L was on sale at REI) (Final weight: ~30lbs)
Large Army Duffel bag: $23, solidly built and durable (Final weight: ~10lbs)
Jansport backpack: carry-on for a few days, plus day-to-day usage
Also, compression sacks are really useful to make room and keep everything on the small side. I fit all of my clothes in an XL and a M bag and then used another M bag for my sleeping bag + sleeping pad, so consider using them to make travel easier.
(Two compression sacks stored all my clothing. The larger one is the width of a sneaker, about a foot tall and weighs 10lbs! The other one is markedly smaller)
4 pairs of 'work pants': Columbia and Ex-Officio. Check out the Exofficio pro-program for PC volunteers, and check out Sierra Trading Post (SierraTradingPost.com) for great deals on overstock, or last season's merchandise at fantastic prices)
1 pair of jeans
1 pair dress pants (some of the work pants can double as khaki pants if needed)
1 pair sweat pants
1 pair track pants
1 pair swim trunks
2 pair athletic shorts
10 pairs of underwear, some are travel or underamor which can be washed easily and dry out
5 pair of Smart Wool/REI hiking socks (once again, check Sierra Trading Post)
6 pairs of regular socks
1 pair soccer socks
1 pair formal socks
2 belts (one leather, one fabric)
3 t-shirts: Pittsburgh Penguins shirt, Doink the Clown, and College of Wooster PB shirt
3 solid color travel t-shirts
2 long sleeve t-shirts
2 long sleeve shirts button downs (one solid color, one striped shirt for 'going out, but looking nice')
2 short sleeve, button down shirts (plaid, of course)
1 flannel shirt
1 short sleeve polo
1 packable rain jacket
1 rain jacket with a bit on insulation
1 fleece jacket
1 pair dress shoes
1 pair running shoes
1 pair hiking boots
1 pair sandals (could be bought in Peru)
Soap/shampoo combo (one bar)
3 tooth brushes
2 tubes of toothpaste (more than enough)
Floss (According to my dentist, flossing is the key to prevent any tooth/gum problems while abroad)
Contact lens solution
A year's supply of contact lenses
2 pairs of glasses
2 pack towels (1 XL, 1 Medium)
Athlete's foot spray/foot powder
1 Leatherman Wave (check eBay, they're much cheaper)
1 Leatherman knife
Photo prints of family/friends/home
Digital camera, memory cards
Rechargeable batteries (AAA and AA) w/ charger
Travel speaker for MP3 player ($20 at Best Buy, good sound quality)
2 Thumb drives
External, USB powered hard drive (as a backup and to store movies)
Simpson DVDs (also in Spanish!)
Deck of cards
Travel alarm clock (runs on batteries and decently loud)
Travel alarm clock (runs on batteries and decently loud)
Sleeping bag/sleeping pad: we do a lot of travel to other sites, so it's helpful. Plus, from my experience with mattresses in foreign countries, sometimes you need a little extra support.
Few random things:
Terrible towel + Pens rally towel
A few small desk items that have been following me around for some time
(From the Osprey pack: sleeping bag and sleeping pad (stuff sack), other purple stuff sack, toiletries/contact lens solution, pack towels, insulated coat)
So I'll try to update at some point and say what's kind of useless to pack. Just remember that you don't need EVERYTHING on the packing list, and you can get most of anything wherever you're going...and if not, you probably don't need it!