What kind of system do you have? I'm kind of curious how mine would hold up. I'd give the demo a shot, but I'm more of a HL2, CS:S fan.
I built my system myself on a ASUS SLI Premium Socket 939 motherboard, Nvidia Ge-Force 8800 640MG Video Card, 2 gig Corsair Twin Sticks DDR 3500LLPRO paired RAM, 650Watt coolmax powersupply, 4000+ Clawhammer AMD Athlon 64 2.4Mhz processor, which is the equivalent of 3.5 Pentium 4. I run all my games maxed out at 1280x960 rez. SO far I've been able to play everything new. Just finished BIOSHOCK, which is a pretty cool game, graphics are amazing. I upgraded to the 8800 from two 7800GT I was running in SLI... got a 15,550 on my last 3DMARK06 benchmark.
ps. I haven't played counterstrike a whole lot. I do have HL2.
other games I have for my PC
ALL BF1942 & Expansions
BF2 + Expansions
CALL OF DUTY 1 & 2
FarCRy
F.E.A.R.
ALL Rainbow 6 games including Vegas
Splinter Cell 1 & 2
Ghost Recon 1,2 and Advanced Warfighter
SWAT4
Dark Messiah
ALL Unreal Tournament
Might be 1 or 2 more I am not thinking of.