I'm one of those people like Paolone warned you about.
Seriously, many of us use the current Amiga-like OSes (AmigaOS 4.1, AROS, MorphOS) every day as their main machine. A quick rundown:
AmigaOS 4.1: Most expensive, but the only one based on AmigaOS 3.x. Very advanced under the hood, and my personal favourite... but it costs. Very expensive new hardware coming very soon (Sam 460ex, AmigaOne X1000).
AROS: Completely free! Runs on PCs so you don't need new hardware unless yours isn't supported, but if you don't have supported hardware it's still very cheap. Very fast development as it's open source.
MorphOS: No new hardware - you need a second hand PowerMac preferably. Cheaper than OS 4.1 (but still costs for the MOS license) and very fast; very similar to AmigaOS but not directly based on it.
If you just want to run games, though, don't bother with any of them.
They all can browse the web quite well (OWB is the browser), and they're all pretty fun to mess with. Personally though I wouldn't let my AmigaOS 4 machine go. And I own all the above.
