I think most laptops are fairly well spec'd these days, and you can probably do no worse than the offerings from Dell - certainly for price. But if you're in a IT Dept, do they have any purchasing deals with their suppliers? or what spec do they all use?
The main point of a laptop is portability and small footprint, followed it seems by style, so as long as you have a big HDD, at least 512Mb RAM, as fast a processor as you can afford, and probably a DVD-RW or if not a CD-RW you should be fine. A 15in (or bigger) screen is desirable, and a good case (for it and the endless cables, adaptors etc.) should cover it.