Buy the 3500+. The 4000+ is far too expensive for the extra performance you would get.

If you want stability, I would consider the Asus A8V Deluxe. For overclocking, I would go for the Abit AV8.

For rendering, the best route would be professional 3D graphics cards, which cost a fortune if you choose top of the range. Otherwise, I would just pick out a 6800GT. The only difference between it and the ultra is reduced clockspeeds. Plus you will easily get 1.5 years out of it.

Looking at this, it seems that higher quality RAM gives you some big performance increases. Any arguments with this? Did I read something wrong?

Its always been a fact that more RAM means more power, also the qaulity counts. I mean you cant buy shitty RAM for 5 bucks and expect it to run like Kingston.

You're correct oeone. There is a performance difference but it's not dramatic at all. Most of the 'Value' lines of reputable manufacturers operate at CAS3, while the 'performance' lines operate at CAS2. That makes for a noticeable difference, but by no means a dramatic one. It is, after all, only one small factor in overall system performance.

Besides, if you purchase RAM modules which are rated a speed level ABOVE what you wish to run, you'll most likely be able to operate it at tighter timings anyway, when you clock it back a bit