Here are my suggestions for pre-built desktops (I didn't really look at any other OEMs besides Dell). Lenovos are pretty good but quite pricey. I'd go with the Optiplex 990 since it comes preinstalled with XP mode and is Q67. But it's interesting to see the large price difference when the hardware is virtually identical

Dell Vostro 260 Good - $530
Discounted Vostro 260s. (Preconfigured) <- Preloaded with discount codes. $80 bucks more if you configure your own.
[Linked Image from ]

Downsides:
-I can't verify if these support PXE should you decide to use a WDS Server for deployment.
-These are based on the H61 chipset (Home). The ones in my recommended in my suggested section use the Q67 Chipset (Corporate). Q67 is pretty much guaranteed to work for deployment. Everything is Intel based.
-No Solid State Drives (SSDs). These will give you the lightning fast feel. Probably the biggest improvement over older computers by far. People blindly keep adding RAM/memory to their system. It's usually the hard drive that's the limiting factor nowadays. Most people* don't use over 3GB of memory, even gamers. So 4GB is enough. You can add more later.
-1 Year Warranty (can upgrade to 3 for ~$100)

Optiplex 990 Very Good - $794
Dell Optiplex 990 <- Click Here for Preconfigured Desktop
[Linked Image from ]

You can downgrade to the 250gb hard drive if desired.

Downsides:
-No SSDs. You can add this afterwards too. If you do go with an SSD, you should downgrade to the 250GB hard drive.