How far are from the end?

From having a nearly unupgradable computer? I mean, my system is basically one of the top gaming systems you can build (XP1800 oc'ed to 2.4GHz, 512MB of BH5, a 74GB Raptor, a 9700AIW, an NF7-S, and an Audigy 2), so it's getting kind of hard to upgrade anymore. I think that the only thing left that's actually worth it would be the power supply, to add more stability to my overclock, and to find a mate for my single 512 stick of BH5. Outside of that, I don't really see much left to upgrade.
Today, I found it worthwhile to get a UPS to protect the whole thing. A very valuable upgrade to me, but completely useless in terms of any sort of performance enhancement.

So the question is, how much more money would you have to spend to get your computer to a similar point as mine? If you guys feel like sharing, what is it that you need to upgrade?

Please don't go crazy and say you want to upgrade to quad Xeons with 4 gigs of RAM or anything like that; I just want to know what would deck out your computer for the platform it's at now (Socket A for AMD XP's, and whatever is Intel's main socket right now). If you're using an older computer than PentiumIV/AthlonXP, then just denote that your entire computer needs upgrading.

Thanks guys, I'm looking forward to seeing the responses