If you are not gaming, take a look at the Lenovo desktops. Particularly the M92, E31 (workstation). and S30 (Xeon Workstation)
IMHO, much higher quality than HP and all 3 models include a 3 year, next business day, on-site warranty. For about $30-$50 you can upgrade the warranty to priority support out of Atlanta or Toronto.
The E31 is a particularly good desktop at a reasonable price.
The S30 workstation is their direct competitor for the MacPro, but for my needs, it doesn't offer any value over the E31.The S30 has all the latest Xeon chips and graphics card options.
I have been using IBM/Lenovo products for over 20 years without problems. USA/Canada support is excellent; India, not so good.
If you can wait at least till November, do so. All PC makers will be doing updates with Windows 8, so there will be extra good deals on units with Windows 7. Lenovo is constantly running "sales" and you can get good deals in their Outlet Store
If you want to run VMware, be sure to get W7 Pro / Ultimate. Home Premium won't work
I have been waiting and waiting (like many others) for the iMac / Mini refesh and looking at the MacPro but decided to go the PC desktop / Mini combo.
I need a PC for business stuff (plus multiple HDDs/ replaceable components. etc) and will buy an E31. I will use the Mini for digitizing analog music / photography/ Fun Stuff / Music-Video server.
The current MacPro is more than adequate for my needs but the E31/Mini combo is a much better value and more flexible