As someone who is young, I would tell you to take the job, especially in this economy... For now.

Tell whoever in your company what you are thinking (if you trust them) and then agree to the extension. Work hard, get the other year of work experience (save some more money in the process) and at the end of 2010, travel. If you really like the company, you can try to set it up in that you will return (ie. have a job waiting for you). This will be easier with another year of experience under your belt and you'll be a known commodity to your boss, team and the Firm.

Frankly, I don't think 1 more year of work experience will result in that much "investment" from the company on their part, but I could be wrong. I also don't think 1 more year will go too far into "locking you into this company and career" to be honest. BUt you never know.

2 years of work experience is more helpful and looks much better than one. Plus you'll probably have more money saved up which means you can travel for longer and/or go to more places.

FYI - I went to study abroad for a few years and then joined the workforce. Don't regret it for a minute. You're young (so am I), so nothing to worry about. Feel free to PM and I can get into specifics.