I myself have been sitting on a slightly old, but fairly up to speed rig; a good CPU (AMD Phenom 4X) but clearly the GPU is where it is on the mining scene, and the best I've got is an HD 4XXX series card (I forgot the specific model #). If I get such a rig setup w/ say, that custom linux distro for mining, could I get my system working well enough to get a bitcoin or a few every week? Or would I have to hunt down a stronger card?
I have approximately 2.5-2.6 G/hashes between my systems. I can reasonably expect to average 1.5ish BitCoins per day. You would be lucky to get 0.5% of my hashrate, even with one of the best 4000 series video cards. I don't intend to discourage you, but unless you have a 5700/6700 series or higher it's probably not worth the cost of electricity and you could expect to lose money in most places (depends on your electricity rates).