If you only access to one system, the one you are blowing away, I personally like to have all the Dell drivers ahead of time, just in case you have a problem with NIC or Internet connectivity afterwards. They make it really easy to get them and the one's on the website are in some cases, newer than what came with your system (Cd's). I use the Premeir support and Enter the Service Tag on the Dell support site and go to Downloads. I like to save them in folders with relevant names, versus the random number file name Dell uses. So I end up having a folder for Chipset, video, audio, modem, NIC etc.. Get all the drivers and burn them to a CD so you have the very latest versions.
When you double click each downloaded driver .exe file, it usually launches Winzip to extract. I usually extract them to the same folder the .exe is in, so they are are in the folders mentioned above. (you can copy and paste the path from the open folder into the extract path in Winzip) (Of course, if you had them on CD you couldn't do that, so I copy to a c:\dell folder on the HD after formatting)
Getting the drivers ahead of time makes things really easy and quick. You can install all the required drivers very quickly after a clean install.
Once you reformat and install Windows XP, install the Chipset Drivers first thing. This will allow other devices to be recognized by XP.
Once you reboot, go back and do the others (Audio, Video, Modem, NIC,etc). I usually don't install the extra Dell software like Open Manage (that may only be on the Latitude series though). Also, you don't have to reboot for each item you install. Just install each one and when prompted to reboot, just hit Cancel, and do the next one. Then just reboot after you have done them all.
Once your back up with all the hardware, don't forget all the Microsoft Windows XP updates!