Q8300 or Q6600?

[arthurleung]

Wouldn't recommend the Q8300, the multiplier is way too low to be any useful, unless you're not going to overclock.

I have both a Q9450 and Q9550 and they both struggled to overclock due to northbridge (Tried P965, P35, X38). My CPUs runs at below stock voltage and adding any voltage doesn't help pushing above 430FSB. Using 2x2GB set of memory doesn't really help either.

[12GaugeShotty]

Another vote for the Q6600.

Some of the 8300s don't support virtualisation; The SLGUR (order code AT80580PJ0604ML looks like the pick of the bunch) is the version that does, whilst the SLB5W does not;

http://ark.intel.com/Product.aspx?id=39107#specs

VT-x won't matter unless you use applications that need it, which is primarily for virtual machines (VMWare, VirtualBox, Windows 7 XP Mode).