First off let me say thanks to everyone who has replied informatively to many of the threads in this forum (Vehementi especially). I finally got some spare time thanks to the Christmas holiday period & decided it was time I got around to tweaking & overclocking my system.
So after reading quite a lot of posts on this forum I now have my XP2500+ running at 400mhz FBUS (as in XP3200+ speed) which is nice & am experimenting with overclocking my Radeon 9600 non-pro (once the X800's drop in price a bit I'll probably purchase one of them but it'll do for now).

For anyone that is interested my CPU temp used to sit around 34/35°C and hit 39/40°C when under stress now it idles at 38/39°C and sits between 40-42°C when I stress it (I have 2 case fans on the front of my case for intake & 2 on the back blowing out, system temp sits around 28°C unless I take the side off the case). Those values are without CPUIdle Extreme running.

Now for the questions. My CPU-Z report is here -> http://homepage.ntlworld.com/dj_sanders/cpuz.html
Motherboard is a DFI NF2 Ultra Infinity & my CPU cooler is an Coolermaster Aero7 Lite which I have on full speed all the time as it doesn't make enough noise to bother me.

1) Should I lower the memory timings if at all possible for better performance? I currently have them set on Aggressive & SPD in the BIOS but should I manually set the timings instead? I will be purchasing another 512MB of the same manufacturer & model in the next month so I can use the dual channel interface which I am led to believe gives higher performance.

2) I currently have the AGP aperture set to 128 on the recommendation of this article as it is has 128MB onboard RAM. Should I leave it as is or would it be better to change it to a higher or lower value?

3) What drivers do people recommend for nForce2 chipsets? I installed ones I found on the DFI website after updating my BIOS which have the version number 5.10 (they're linked on the drivers page from the motherboard specs page I pasted above) however the NVidia site only has version 4.27 drivers available.

I'll probably have some questions about BIOS settings later once I restart & grab a pen & paper but for now thanks for reading.

[edit] forgot to mention CPUIdle Extreme really is the business. I use my machine for gaming & coding/compiling and its great for chopping a few degrees off the CPU temp when I'm not doing anything intensive. I use it in S1 mode as C2 isn't supported but I've not tried OS yet.

If the system runs fine with the memory set at aggressive just leave it there.
128mb video aperature is fine.
I always use the video and chipset drivers from ATI and nVidia because they are usually more current than the ones on the manufacturers websites.

Yeah thats what I've always done in the past but the DFI site has version 5.10 which I'm using right now where as the NVidia site has version 4.27.
Just seems odd to me.