Quote from Dustin:
I just bought a new Dell last week. I found a 4550 Dimension with 2.4ghz, 640mb ram, 30 gig hd for $630. My only problem was that it came loaded with XP Home. I have Win2000 pro disks so I will overwrite if needed. So, I called customer service to see if I could get 2000 pro pre-loaded on it. He recommended the Optiplex upgrade which is more customizable, but nearly 1.5x the price. When I told him I would just overwrite XP with my 2000 pro disks he said "well for what you do (trading) you need a strong computer, and with the Dimension you are just getting a little home computer...and you are just nickle-and-diming." (By the way, I've been using an old Dimension for years that has been great.)
That offended me and soon I hung up. Honestly as far as I can see most of the internal components are the same between Optiplex and Dimesion, it's just the customization that costs more.
Just don't trust Dell reps to get you the best deal.