Best Computer for Quartus Compile Times...

I built an Intel Core 2 Quad system specifically for compiling and simulations, however it never went above ~1.5 for the average number of processors utilized, even on larger projects. I ended up replacing it with a faster 45nm Core 2 Duo and am now achieving better compile times.

As for 64-bit, I run Windows x64 natively and x32 in a VMWare virtual machine on that system. I'm not able to use it today, but I'll try to remember to do a benchmark later to see which is faster (as I'm curious about it, myself). I'm sure the native version will have a slight unfair advantage due to it not being in a virtual machine but I can't imagine it'd be much given the virtualization support built into the processor.