Since you didn't say what your budget is I'll just give some general info.
For the most part just about any New PC will do the job.
Since none of the software you are using places a high demand on the PC.
So, 2.8 Ghz. processor 512mb ram, 120Gb HD, 128mb video card will do the job.
Get nice 19" LCD or CRT display.
XP Pro has better networking and security than Home XP.
You didn't say what you office has 1 PC, Multi PC, server??
Do you need on site service? Fast responce time? If you have problems?
So a little more info would be helpfull. John
I'm set to purchase a replacement PC for my office and have been looking at the Hewlett Packard's and Sony Avaio's
I don't need a computer high in graphic or media capabilities but rather, one that will handle wordprocessing, databases, some desktop publishing but most importantly, accounting software.
I would also want good display quality as the majority of my day is spent within the accounting program and a good display is VERY important.
I have heard that XP Professional might be the preferred OS for running standard business software
Can anyone give me some hints on what is the best choice?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic