what kind of overclock could i get

[scubes]

hi guys im wondering when i have to overclock what kind of overclock will i get outa my current system.
here are the specs.
intel core 2 duo e 6600
gigabyte ds4 default bios
3 gig kingston value ram ddr2
maxtor 120 gig ide (winxp)
maxtor 200 gig sata(winvista)
gainward geforce 8800gts 640 meg
audigy2
nec dvdr

hope you guys can help ...

cheers colin.....