You don't really give a lot of information, but let's have a look.
I guess this is the one with 800 MHz front side bus, and not an older model. Xeon processors are usually for servers, and they are not very used.
As far as I know the advantage of the Xeon processor is that can be used in multiprocessor configuration, and you can use 2 of them on the same motherboard. That rocks.
It should be possible to get it at faster frequencies, though
RAM is always good, although 4 GB might be more than you need. What you have to check is the speed.
If I'm correct you should have PC3200 in dual channel configuration
this is also a lot. Here you have to check, besides the rotation speed (but it won't be more than 7200, I'm afraid), the interface. The best is SATA 2 or SATA 300, but you should have at least SATA 150
64 MB PCle * 16 nvidia, Quadro NVS 280, Dual VGA Graphics Card? (really don't understand any of that except that it can handle 4 monitors)
This doesn't seem to be great, but you don't play games, so it should be enough. Apparently this is for 2 displays. Do you have 2 of them?
Will this be a competent system? Is there anything else I need to be looking for?
it looks pretty good, although you are probably going to have more a server than a workstation; for computation intensive tasks it might be not the best. It depends on what you have to do.
If you don't buy a machine from a big manufacturer you should also make sure that the components inside (motherboard, memoty, video card, etc) are of a good quality, but considering the level I don't think it's an issue
Also, I assume you will have some sensitive data. To make some backups you can use the CD/DVD writer that you are *surely* going to get, but if you want really a cool solution check if you can get a couple of hard disks in a RAID. In that way whatever you save will be automatically copied.