your resolution is not very demanding at all. if you plan to keep your monitor, a card like the ATI 5670 is more then enough to play the game at high settings and get 60 FPS. The new expansion will not be any more demanding then the current WoTLK expansion. The old zones will get make overs. The Nvidia 9600GT and ATI 4670 are cheaper solution but lack the ATI 5670 performance.
as for a CPU, WoW likes two fast cores. A dual core would be your cheapest option (but limit you in newer games), followed by three and four core CPUs. look for speeds 2.9ghz +
Sorry to keep asking stuff, but do you think having a "Intel® Core™ i7 930 Processor (4x 2.80GHz/8MB L3 Cache)" would keep me at 60 fps while filming with fraps, or should I get a "Intel® Core™ i7 960 Processor (4x 3.20GHz/8MB L3 Cache)"? This is assuming I have the "ATI Radeon HD 5670 - 1GB - Single Card".