With the size of the cache on that chip and the fact that it is multi-core, you will not need to overclock it at all.. in fact.. overclocking on some thing like that kind of defeats the purpose of buying some thing like that for convenience.
I didn't look at the rest of the specs, but I think you could easily put together a system for less than $800 but that processor base. I tend to stay away from the cheaper "budget" ASUS boards.. they have always cause my friends and my self to have troubles.
Get at least 1 GB of RAM, I think 2 would suit you well.
What are you doing for your operating system?
After using Vista, I can't see a reason to use it; it is a piece of bloated malarkey. Give it a few years if you are even thinking of buying it. If you get Vista, get at least a GB of RAM.. though.. 2 tends to be much better. Windows XP should suit you fine; extract your key from your current machine (if legal, of course) and use it for the new machine. There are a host of extraction tools out there;
example.
There are better ones which will also tell you any Microsoft key on your machine, but I can't find the one I use... and can't remember the name.
So.. yeah.. I think you should aim for this stuff:
-2 GB ram (1 GB minimum)
-XP for your OS (or linux if you have a ported version of tribes)
-Firefox for your browser (the new IE really doesn't do it for me; the only thing I know I like is the convenient print icon.. but that's about it!)
-don't overclock.. waste of your warranty and takes away from the convenience of the processor in the first place.. but that's my opinion here.
I have been out of the hardware loop for a while.. so I am not as informed as I usually am; I would wager my advice is better than most, though.
Peace!