I haven't read everything, yet, but this is what I think about the AMD or Intel question.
Today AMD is the best to get, mainly because it runs a lot cooler and cheaper (consumes less energy) and also possible more quiet.
For speed I would also go for an AMD, nowadays they have SSE3 too, but if you go dual core, I would go for Intel (only speed wise) because they offer dual core models at higher speeds.
If you go budget, I'm not shure, the Semprons are relatively cheap, and the Celeron D are better than normal Celerons. I'd go for a low speed S939 Athlon64 instead of a sempron or celeron.
Price wise; if you are a REAL gamer, go for the FX57, lots of power, lots of overclocking but hiiiigh price.
For Dual Core, I'd suggest Intel, because they are cheaper.
For Single Core, go for AMD.