Currently intel core 2 duo 6300 to 6600 are pretty good cpus if you want to build a good system.. 6700 for an expensive one. The 6800 is pretty extreme but doesnt offer enough to justify the costs.
Adobe software runs fine on AMD and Intel, depending on what you do with it it needs enough RAM & a big hard disk.
I think it runs just as well on a pc as on a mac, but ah2 has some complications on the mac i heard. Also at the same performance the macs tend to be more expensive. They provide good quality for it though.