I think Dell has the Mini 9's on sale again for $199. IIRC, it may only be 4GB or 8GB, but IMHO, you should upgrade it to at least 64GB. I have mine as a dual boot, you could go triple if you want. It has Win7 and OSX 10.5.8. No Snow Leopard yet, waiting for the Hackintosh devs to complete the installer, right now audio seems to be the last thing not working but they are close.
LOVE my Mini 9. I've taken it on trips to the Philippines and Canada and no issues. I love the size and battery life can go to almost 4 hours if I shut off Wifi and BT. I also use my headphone USB DAC to listen to AAC lossless on my Grados with iTunes. Sounds great. It has Skype and we used my Skype out to do international calls. It doesn't handle MKV files well, but it is a low end machine. AVIs are fine. Great for trips because of the SD slot to off load camera pix.
It's not that hard to do, more than happy to help you if you decide to go that route.
http://www.mydellmini.com/forum/http://www.mydellmini.com/forum/mac-os-x/The Mini 10V is also nice, it may have better video handling.
Although I really love Macs and OSX, I do have to admit that Win 7 is great. It is FAST. I tried it on my Macbook using VirtualBox and an external HDD. It was faster than my Parallels Windows and faster than my Thinkpad T41. You could also forego the multiboot and put only OSX. Then use Virtualbox to run any other OSes you want to try.
My friend went the Hackintosh route w/ a desktop version he put together for under $500. He really likes it but you have to more conscious of the OS updates and install packages. The biggest advantage of the Mini 9 is that once it's working, you can (usually) just run standard Apple updates w/ no issues. W/ other hardware, you have to wait for the devs to create specific installers to match your h/w config.
