Pitfalls are that new motherboards are phasing out IDE, the latest INTEL chipsets are only supporting 1 IDE slot. With all your hard drives that may be a problem.
If you get a new motherboard you should get a new CPU and RAM, otherwise the improvement will be very small. Also, the new motherboards probably won't support your CPU anyway...
If you get a new CPU, i would advise waiting until August when the new INTEL Core 2 Duo (Conroe) is out. Read here all about it:
http://news.com.com/Core+launch+mean...3-6081866.html
Get an ASUS motherboard too, these are the best quality and seem to work very well with DAWS. You could check somewhere like
www.cubase.net to read about various DAW setups?
Good luck!