Most American airlines let you carry some pretty serious baggage anywhere you go. In Europe, not so much. Is it because Americans buy and lug around more stuff? Maybe, but European travelers tend to have a "home base" where they can leave the majority of their stuff when traveling to other EU countries. You, crossing roughly 3,000 miles of ocean, won't have that luxury. And they'll charge you for it.

I was planning to use RyanAir for a quick hop from Dublin to Germany ($150 USD). When booking my trip, I clicked on their 8pt font baggage details link and found that I can carry a maximum of 15kg (33 lbs) of luggage, and everything over that is billed at $9 EUR ($13 USD) per kilo! I pack pretty light but I'm staying for five months and two seasons here and also doing computer science research, so I have various bits of heavy computer equipment and reference books with me. Not happy.

That's when I discovered the hottness that is the Eurail Select Youth pass.