Add this. Maybe it'll help with the CPU choice between Intel 4-cores & AMD 8-cores. 3 things I basically do:
1. I game. NEVER on-line. My games are almost entirely simulators. SimCity4, upcoming SimCity Limited, Trainz 2011, Cities-XL, Tropico-4, Civ-5, junk like that. I'm not running & shooting, but sometimes (often) build up humongous maps & metros.
2. I'm an author. My books are almost always 1 of 2 genres. #1 is novels built around events which could, or have, happened. These require LOTS of research, so sometimes I may have 50 tabs open on 2 different browsers + my text editor open somewhere else. I figure this type usage is more bandwidth/memory intensive, but it does use processor power also. #2 type is BIG eye-candy books, the expensive type with large pretty pictures & little writing which you leave open on the end-table to impress your friends. Here I may have much fewer tabs open, but they will each contain large hi-res images. I may also have 1 or 2 image editors going (Photoshop, Ultimate-Paint, format changers, etc.) So I figure this type is more graphic intensive, less bandwidth, about the same memory.
3. I'm a very active & somewhat advanced astrophotographer. The images I take through the scopes via CCD are B&W exposed through 4 color filters. The result is a set of "FITS" files, usually around 1500X1200, & often up to 300MB each, depending upon how long the exposure was. All 4 of these will be open at one time in Photoshop, while I align, crop, adjust, etc. The final, usually 500MB'ish, then goes through a converter to make it into hi-res TIFFS or lower-res PNGs. VERY high memory usage, CPU, GPU, everything.
Maybe that info will help a little on which CPU-type is better.