You'll also need your MIS department to hook you up. If you have a NIC, you'll probably only use your modem for faxing. If you don't have at least 2MB of video memory, get used to spending some time watching your monitor catch up to your computer. You've got to have one unless your MIS department is going to install all your software over the network. These are what you use to connect things to your computer - printers, keyboards, etc.
All computers fail sometime.
If you have to use floppy disks, make sure you keep copies of all your software and be prepared to spend hours recovering from a disk failure. Sound is a luxury in the workplace, but nice if you can get it. You'll want a sound card to run your speakers, headphones, and microphone. It's hard to work without one. Ink jet printers are fine and color is affordable.