I'm kinda curious - is there anyone who doesn't regret their twenties? We've got three posts regretting working for the wrong startup (mine, menloparkbum, and gscott), one working for a big company (yours), one going to grad school (timcederman), one getting a degree (jobeyonekenobi), and one doing nothing (johnyzee). So apparently working for a small company is bad, working for a big company is bad, not working is bad, and getting educated is bad. What should one be doing?
I'm not sure that "What should one be doing?" is the right question. I tend to ask myself that question a lot and I've drawn the conclusion that it's how you do things and what you learn from them that counts.
I know some folks that did that and regretted it. Well, maybe not the travel part, but I've got various friends that have started bands/gotten arrested/had fun and kinda wish they hadn't.