Hey Guys,
Just started mining as well. I have 3 Windows machines, 5 58xx cards (slightly overclocked), use BTCGuild pool and am hashing the day & night away
I also mined CPU, didn't go as fast by far, but had no problems using my PC for heavy duty graphics work. No noticeable lag, apart from my hashing rate going down. 8 Cores, that might explain it.
I hope to be here for a long long time, while I am learning !