I haven't upgraded to any of the service packs. I didn't really see the point :o) My computer works fine
Really bad idea -- there are numerous remote exploits that your computer will be surceptible to without the servicepacks. It will be a matter of time before someone breaks in.
There's a good chance your computer is already part of a botnet relaying viagra spam as we speak, without you even realizing it. Most of the current crop of trojans/virusses don't kill your computer or files anymore, they'll simply hijack it to do their bidding -- it becomes part of a spamming network, denial-of-service attacks on large websites, re-routing traffic so a criminal can hide their true location, etc.
If you don't do it for yourself, you owe it to the rest of the internet to keep up to date on your security & service patches... Others who are on the receiving end of all that crap get to suffer because you don't see the point to protect your computer.
Studies have shown that the average length before an unpatched XP or Win2000 machine connected to the internet has been broken into (just by being connected, sitting idly) is down to about 15 minutes now. Be responsible!