For a business PC this is a decent piece of hardware, it is fast enough to run most business applications, while still being cost effective.
I do not like all the bundled HP software that comes loaded on these. Our company orders these with XP Pro SP2 loaded on them (downgrade).
I noticed a very high network utilization coming from there at night when there should be no activity and looked into it further. I wrote an article found here http://reviews.cnet.com/desktops/hp-business-dc5800-core/4505-3118_7-32856705.html discussing what I found and how to correct the problem.