The key with Vista is extreme RAM usage. A “clean” install of Ultimate ed w/ no other software running will take between 600 and 700 MB of RAM. Shutting down all non-essential services and even a few really important services will leave the machine at 400MB of RAM usage. I’d suggest that machines run with a BARE minimum of 1GB of RAM for Vista. Bare Minimum being defined as someone who’s only using the machine for word and office. For others I’d say a minimum of 1.5GB, probably 2GB.
The second issue of concern is the graphics. Aero is a memory hog. If a machine is running a graphics res of more than 1024×768 it will require at least 128MB of video RAM. Dual screen will easily require at least 256MB of video RAM. This will be ok for machines like the D620’s, for other machines you can set the graphical theme back to “classic” (same as classic on XP — which looks basically like Win2K). This setting allows elder computers to run “normally”. As cool as Areo looks with the transparency, it serves no useful functions what so ever. In the need for speed, I’d say turning it off to be the best solution.
Another borrowed trait from OS X (like Areo) is the default for the OS to run as an unprivileged user (even as Administrator). I’m not sure if this is helpful what so ever, as users love to click “ok” to everything (Note: It does not ask for password). A small shield icon (like the one used for security center in XP) appears on the bottom of almost every button and icon that requires escalation, which is basically everything. Personally I think this feature is EXTREMELY annoying, and wont be of any use. There is are a few GPO’s that can be modified to disable this “click ok” feature and have the logged in user running as privileged.
Vista does has an interesting service it calls “Application Experience”. With this service running, if Vista detects a program did not run properly, it will attempt to emulate the proper version of windows for the application. This has personally worked well for me, to allow me to install programs that are “2k/XP/2k3 only” under Vista.
Another service of interest, and annoyance, its Windows Defender. The main annoyance is that if you disable the service — Vista will complain upon boot. Every… Single… Time. There doesn’t seem to be any way to stop this.