(Yes it's a 4 year old gaming rig)
2x nVidia gtx275
1x i7-920 (using cores 1, 3, 5)
Totals around 110MHash/s.
Stopped mining after it almost killed my CPU fan though

really??? MHash/s ?
i own a i5-3570K and a Radeon5870
GPU@guiMinerScript_alpha: 395kHash/s
CPU@YAC: 60-140 kHashs/s
do you get really 110000 kHashes/s ?
what do i wrong?
I dunno, using
GUI Miner on Slush's pool, created 3 miners, one using first GPU, one using second GPU (both OpenCL) and the third using 3 cores (A single Ufasoft CPU miner).
Note though that GUI Miner is a bit bugged, it uses one core 100%, so don't assign that core to your CPU miner otherwise it gets nothing done.
[edit] Just for clarity: merged mining of BTC and Namecoins, not LTC [/edit]