don't get a 845pe based motherboard because you loose the advantage of using rdram.
The ram bandwith of such a mobo is not bad but still not as fast as rdram. about 2300 Mb/sec for a 845 pe and over 3000 for a 850e with good rambus.
I currently own an asus P4T533 with rimm 4200 and I'm very happy with it.
I'm close to 3700 Mb/sec which is by far the highest bandwith you can get right now. If you don't want to overclock the cpu, you would still be around 3300 Mb/sec.
This is what makes a difference in Maya or any other 3d app or compositing ( Combustion loves it)
I wouldn't buy the 2.8Ghz though, it's too expensive.
Get the 2.53 and slightly overclock it. You'll have the equivalent of a 2.8 for a lot cheaper.
If you want me to tell you what to get part by part, I will.
Dave