I did this a few years back, sold a PC I figured I wouldn't be getting a lot of use out of. Yeah, like the rest are saying... I think I went about 4 months, using a Laptop, before I finally caved and just bought the parts for another PC. I absolutely hated using my Laptop. It's decent, like others have said, for web browsing/music/social networking/word processing (work related stuff/uni related stuff). But for anything else, you may as well use a PC. The longer loading times, the inability to upgrade it over time, the fact that you will MISS playing games at some point... they'll all add up to become one big annoyance and you'll regret selling the PC.
Even if this post is a little "Eh..." given what he's saying, and his post count... I figured I'd respond anyway, as you never know... I could stop him from making a silly mistake!
Either that, or he'll completely ignore me. Who knows.