Are you going to be running quickbooks on it? How about UPS world ship? I would get more than the 1gb of ram that it comes with in the base model if you are running vista on it. No need to go over 4gb if you are only going to run the 32 bit version of vista. Mostly look at what software you need to run and see if it works on vista. Dell has pretty good support. I usually look at
TigerDirect.com - Computers, Computer Parts, Computer Accessories, PC Components, & Electronics
to see if they have any good refurb deals before I shop for a new pc. You can purchase an extended warranty from tiger direct and get more computer for your money from them.
But all in all, I think Dell is a good buy.