Just my three cents:
1. You can only upgrade from 32 bit to 32 bit, otherwise clean install.
2. You can only upgrade from 64 bit to 64 bit, otherwise clean install.
3. Don't buy 64 bit unless you know your CPU is 64 bit capable.
4. Go 64 bit on a server, won't give you much of an advantage on a client.
5. I would recommend WIN7 Pro over Ultimate or Home Premium. Easier to connect to a domain, has Windows XP mode, and more backup options. Ultimate gives a bit more security and the ability to work in Japanese or Norwegian.
6. I would go with full workstations and not thin clients.
7. Whether peer to peer or client/server, go with 64 bit if you can and run a lot more RAM. Most client OS can run up to 128GBs of RAM (a little overkill), network OS at 64 bit either 32 or 64. You really don't need but more than the 3.2GB you get on a 32 bit client.
8. While there will always be a huge debate over client/server and peer to peer, I will always recommend client/server. If you don't have a server, then peer to peer is fine.
*** I think many times when we talk about P2P vs client/server, everyone concentrates on AC. Most offices run other applications than just AC, I would hope. A domain gives you a ton of advantages, although with a price.
BUT....for me a P2P is boring!
No offense.
And, I just personally hate to have anyone working on the computer that has the databases on it. The whole idea of a server (well one of them) is to have it run without touching it and maybe reboot it once every three to six months.
PS As far as specs go, just about anything these days in a client will suffice. You would be hard pressed to purchase a computer even bare bones that wouldn't run most programs sufficiently. They are giving away memory these days. Just concentrate on the main computer (whether a true server or the computer on the P2P designated as your server). Give that one all the RAM and CPU and faster hard drives, etc.
OK, that was four cents.
Oh, and one other thing that is too cool. I am not sure about WIN7, but with Vista you can do a CLEAN install with an upgrade disk. Let me know if you want to know how. Save a hundred or so.
