What's the recommended "server" hardware for a new ACT 2011 Premium Installation?

We are getting ready to switch over to ACT from an old program, we've got about 15 users total, but only about 6-8 users that will actively be in the program at a time.  We'll be using ACT Premium 2011 and I'm going to buy a new computer to host the centralized database on our network.  My question lies in what hardware to use.  I've read the Sage website and see all the minimum requirements, but what's going to make it run the quickest?

It appears that I'll just be getting a Windows 7 Professional machine, 32 bit since ACT doesn't use 64, 4 gig of RAM, probably RAID a couple of 500 gig hardrives for plenty of space and some on site backup of the data.  

My question lies in the processor.  I'm going to likely buy a Dell, I figured on one of their Optiplex systems due to the RAID options and likely an Intel i5 dual core processor.  My question is with the way ACT utilizes processing power and the like.  Is there any advantages of stepping up to an i7 or even down to an i3, what about Xeon processors?  I want to get the best machine within reason and don't want to pay for some uber hot processor that ACT might not even utilize all of the power of if I will see no benefit.

So, what's the "best" hardware configuration for something like this?

Thank you,
Jason