I dont know that you should have bought it over a car, but you definitely got a good machine there.
I thought I would add my two cents on the Windows-MAC debate. A year ago I would have been completely hardcore on the windows side of things as Ive been a windows user for ages. Sure it plays games and handles my media pretty well, but when it came time for me to start getting into home recording which made me realize where Windows struggles so badly. I have a pretty decent machine (see sig) and used to have Windows installed and ran Cubase and Cool Edit Pro with a Tascam US-144 interface. What a drag!
First off it took forever to find all the correct codecs and drivers to make these programs talk to Vista and my interface and when they finally did they ran at an acceptable speed but I knew my machine could do so much better than it was being allowed to do.
Long story short, My brother who owns a recording studio recently switched from an all analog setup to an all digital Pro Tools rig with a Mac (dont ask which one, its the one thats only the screen, no tower) and that thing blew my computer out the water in every possible way with less ram and a slower processor!
The final straw with windows for me was that recently I tried to create a new partition to install linux to using vistas partition manager and for whatever reason it fubar'd everything and wouldnt let me boot into windows period!
So now im running Linux and I am bound determined that I wont go back. I got CoD4 running and GTA San Andreas so im set with my two favorite games, audacity for recording, open office for word apps, etc etc... and its all free!
So yeah, i used to love windows, now I dont and probably wont go back until I absolutely have to.