I've built some PCs and bought about the same. Laptops have finally caught up to providing the power and with a few adapters the abiltiy to attach other HDDs when trying to remove viruses from other PCs. The 4 montiors would be great at work if my desk was big enough. Currently I use an old PC (E-Mail, research, notes...) and a laptop (for the real work). I'll be getting to pick a new one next year and will get to pick one within reason on the price and it will be a laptop instead of a PC. I mainly work on application development and some support of databases.

Needs:

17" display minimum

i7 processor (I compromised processing speed last time and won't do it again).

8GB RAM (but if I can get more I will)

At least 1 external monitor port

At least 1 USB 3.0 port

E-Sata

sd card slots

As big of a battery as I can get

Backlit keyboad (letters don't wear off).

DVD burner

Ideally I would get 2 HDDs, but I doubt that would be in the budget

HP has one that I recommended for my nephew going off to college for $800 with all of the above. I need to stick with Dell for work though so the price will be higher. It's amazing how much you can get for under $1000 compared to only a couple of years ago.