Plan on traveling to Europe on a budget, what are the best places and cities to see?

I'm most likely going to be staying in hostels and have only about 10 days. What are some good sites for booking hostels? What cities should I see, considering my limited stay/budget? One option is to stay in a relative's apartment in Cannes for a few days, and go somewhere from there.

There definitely are cities that are more expensive than others, but you can make even the most extravagant city work for you. Do your research way before you get there. Extensive research. A lot of times special coupon books that you buy save you a lot of money, especially with transportation and food. I guess the trick is to avoid the obviously touristy stuff, and to in a way temporarily become a local. Guerilla style. You have to see London, Paris and Rome of course. But there's also Barcelona which is a blast, Bavaria in Germany is like a real-life storybook, the South of France can be a bit blah, but at the same time amazing, Switzerland will make the trip complete, and if you're able to venture into Eastern Europe, then you'll be pleased with Prague in the Czech Republic which has a reputation for being quite an affordable European City. Make good use of the Eurail, making sure you make overnight trips, that way you'll get free board for a night and won't waste time traveling during the day. Have a great trip!

You should check out Twizi.com, they list hostels that cost less than 25 dollars a night. They have cool hostel maps, photos and you can book thousands of hostels through them. Happy Travels and have a good trip!

Their Baorcelona page is below for an example: