>PS -- Why do you say 32-bit is pretty much obsolete? This topic came up not long ago here and some people.I respect, like Rick Strahl, said it isn't even such a good idea. I didn't think a lot of apps even run in 64-bit yet.

If you're a dev, as KG points out some products are currently 64-bit only; that trend will only accelerate.

All of the 32-bit apps I run (admittedly, not a huge variety) run fine on Win7-64.

64-bit gives you headroom. Suppose your dev environment eats up 2GB RAM when running. At best Win32 can only access about 3.5GB RAM, so at most you'd have only 1.5GB free for disk cache etc. If you ran the same program load under 64-bit and you had 8GB RAM in your machine (inexpensive and mainstream these days), you'd have 6GB RAM for disk cache. This can give a pretty big performance/responsiveness boost without having to move to SSDs.

The extra headroom also opens up tons of possibilities for running VMs that you could not do in Win32. Using a product like Sun VirtualBox you can set up an entire network within your workstation, with multiple VMs (32- and/or 64-bit) running simultaneously. Using VMs and snapshots is incredibly useful for testing, amongst other things. Running VMs this way is no longer exotic and unusual; if you haven't tried it yet I highly recommend it. As I see it, this feature alone is worth going 64-bit.