This is my exact situation. I'm 24, finished engineering school 2 years ago, and work as a web developer. My lifestyle has stayed the same (I even spend less on many things). I don't need/own a car and don't really care about buying expensive gadgets...

I'm currently reading The Investor' Manifesto* and it seems I am very lucky to have money to invest in the market. A bear market is a boon for young investors.

By the way, this book is awesome. I regret not reading it earlier. Derek Sivers plugged it on HN almost a year ago (http://news.ycombinator.com/item?id=1026296) and his reading notes are available online at http://sivers.org/book/InvestorsManifesto.