I actually use a laptop at work instead of a regular desktop unit. I then plug external monitor and keyboard into it and I never know the difference.
It is a Toshiba 1.0 ghz with 256k RAM and a 10 gig hard drive. I then have a 19" monitor and it works just fine.
BTW, a friend of mine bought a Dell about a year ago and is very happy with it. I have heard good things about Dell and they are very competitively priced (starting at less than $1,000). If I was buying a new one today, I would definitely check them out.
One thing I really like about Dell is that they typically use non-proprietary parts in their computers. Therefore, if you have a problem the parts are usually off-the-shelf and less expensive. I would avoid Compaq and HP for that reason. A guy I work with had to get a Compaq fixed and it would have cost more than the price of a new one. He threw it away (a little over 2 years old).
Good luck (Opppps, not luck, bite my tongue ... I mean, good forture, or happy sailing, bon voyage or whatever we are supposed to say this week).
*****Rub a Dub