What I'd recommend depends on how long you'd be going for and what level of comfort you can stand
If you don't need hotels & your own room, dorms in hostels are cheap places to stay.
Best time to go is May to early June, college student aren't out yet (of course this advice is useless if you are in college, lol) so crowds are smaller, it's easier to get accommodation. Flights jump up after the shoulder season (I think peak season ends mid-Sept, should start early June). From MA if you can get a cheap flight into NYC, you've got an abundance of cheap flight options- main ones'll be landing in London (Heathrow is more $$$ to land at but more convenient), Frankfurt, maybe Amsterdam or Paris.
Budget at least $50US/day - now this will change depending on what countries you're in. Switzerland and Austria are gorgeous, but will be very very pricey. Spain's pretty good cost-wise. Eastern Europe will be even cheaper, and isn't as overrun once peak season hits.
Are you planning on one country only or going to a few? Rail passes make it more economical, and if you're taking more than one train pick up the Thomas Cook rail spring/summer rail guide in advance. It's a billion times better than the crap schedule Eurail hands out with the Eurail pass.
And if you think Germany would be on your list, go for that meet-up LaFoto is organizing! I think German trains are scheduled down to the nano-second :hail:, just makes it so easy to plan getting around once you're there. And if you are at all a fan of becoming a beer connouseiur, check out Germany.
Best thing to do to give you an overall idea is to check out the Rough Guide First Time Europe book, and the Thorn Tree forum on LonelyPlanet.com.