Upgrade help needed bad

[soundboy]

Here it is I have finally got to the point where I need an upgrade. I am currently running
Win 98se
533mhz celeron
256mb
ricoh writer(ide)
hp writer(ide)
cubase5.0 and a large host of plugins
wavelab
gina 24

I want a faster pc with more memory. In the past I was going to get the ASUS cusl2c and a p3 chip butI am not sure if that system is still good. I am considering going to the SX but dont know what is compatible with it. It has to be pc because I don't know jack about MAC. Is the asus cusl2c a good board for SX and 5.0? And what about P3 or P4 chips. I am looking at the fastest safest chip.Can you guys help me.