>>7
It depends on what you want to use it for. My opinion is that if you're happy with what you have right now, then don't switch.
I switched to the Intel mac mini duo core from an 1.4 Athlon PC in March and I have to say it doesn't feel any faster for most things and my computer usage/satisfaction/productivity is about the same. The only time it feels faster is when I'm watching large resolution videos.
Considering you're posting on 4ch, I'm going to assume iLife doesn't interest you. FrontRow is cool at first but it's very gimmicky. I don't even launch it these days.
It really depends on what you're using your current PC for. If you're just plugging in your camera sometimes and using Windows to grab photos from it, using winamp/itunes to listen and manage to your mp3s, msn to chat, IE to browse and WMP to play videos, then sure the Mac fits your usage pattern.
If you like to break outside the box, go a bit beyond, say you've played with alternate shells like Litestep to make Windows work better for you, or you swear foobar2k up and down because it really lets you manage and play music the way you want it, or have a heavily customised Miranda rocking MSN v10 and a video player like MPC or ZoomPlayer configured the way you like it, then I wouldn't recommend a Mac to you. You're thinking too different and demand too much customisability, Macs don't like that.
I guess if you have a Unix emulation layer like Cygwin installed and it's feeling too lightweight, then OSX's BSD foundation will appeal to you. There's other stuff that's worth mentioning like home/end keys never working the way you think they do, finder's navigation model really different than explorer's browser model and finder's slow refresh rate but those are more lesser points.
FWIW, I crash finder and watch it restart itself more often than I did with explorer on Windows. Not to say it's unstable but coming from a Windows experience that hasn't seen blue screens since bad ram four years ago, I didn't find Macs any more or less stable.