Mac Pro

I would also like to know this. If so / if not, does the difference come mainly from the CPU itself, or from the software environment (OS, bunch of anti-virus etc etc) ...?

So, basically there are no real-world benefifts between a PC and a Mac of similar configurations (hardware); however, that leaves us with the operating systems. In my case, Vista 64bit has been O.k. for pianoteq (anti-virus, and windows defender disabled). Recently, I've noticed some odd behavior from my DAW (Sonar). Most virtual instrument are not responding to dynamic changes; I can play soft or loud; however, the transitions bettween these dynamics are unstable and rough. Sonar used to work perfectly before some recent Windows -automatic- updates. Pianoteq seems uneffected, though. It seems like Windows has a reputation of getting in the way instead of quietly disappearing into the background. Perhaps installing Sonar, Pianoteq, etc. onto a seperate internal drive could be beneficial; I'm considering a SSD for this.

Thanks, EvilDragon. I've heard many positive things about Windows 7; especially in comparison to Vista. I've looked into the Dell XPS 8700 with Windows 7, i7, lots of ram etc. (about $800.00). I just might go that route, after all. Obviously, Pianoteq sounds great, however, one last thing I've been considering (and I'm probably wrong about this) is using a better sound card for improved fidelity. I currently use an M-Audio 192, and can get away with a 64 buffer size (1.3 ms); I notice no latency at all, and the sound is good, but I wonder if an even better audio interface with higher-quality components (audio converters etc.) would make a difference in -improved- fidelty. To be specific, I've been eyeing the MOTU TRACK 16 (usb/firewire) audio interface.