On the subject of clothing, I will offer this advice.
1- Go to lululemon and grab a couple t shirts and polo style collared shirts. The fabric has silver in it that a) resists odor and bacteria and b) THEY DONT NEED IRONING!
There is nothing worse than getting to your destination and wanting to go out for a nice night, then having your only go out shirt wrinkled to shit. The other thing about their gear is that it is very breathable. Europe is HOT in the summer. Like 43 degrees on the Sun coast or anywhere on the Med + humidity is killer for anything of regular cotton material. The sweat on the material combined with the weight of your backpac you will stretch and disfigure a lot of cotton stuff, so after my last trip, realized how awesome their gear was for traveling.
2- The little bags you get when you shop there (LLL) are really nice to have. Get 3 of them- 1 for socks, 1 for underwear and 1 for t shirts. When you arrive in a place, you will never have to hunt through your bag. Just pull out the 3 bags and everything is there.
3- Go to MEC and grab one of the silk sleeping bag liners. You will inevitabley stay in some disgusting hostel bed. These are fairly compact (About the size of a small melon), will save you from gross bed/bed bugs (perhaps) and they are actually really comfy to sleep in in the summer when it is hot.
4- Towels: I just brough a beach towel. I hated those micro towels for the most part as they always stunk and that way you just bring one towel for showering and the beach.
5- Skate shoes are awesome for backpacking. They are comfy and nice for long walking distances, easy to slip on and offer great support for walking with lots of weight on your back.
As Dave mentioned above, sandals are the way to go. Stay away from the super thin beach sandals. Reef's are money as they have an air cushion.
"I believe that banking institutions are more dangerous to our liberties than standing armies. If the American people ever allow private banks to control the issue of their currency, first by inflation, then by deflation, the banks and corporations that will grow up around the banks will deprive the people of all property until their children wake-up homeless on the continent their fathers conquered."
-Thomas Jefferson 1802