I am about to start a web hosting company and have a few questions.

The Facts:

Possible OS's: Mandrake 9.2, Debian 3.0, FreeBSD / OpenBSD

3) HARDWARE Options:

I am looking at:
DUAL or SINGLE Pentium 4 Xeon 2.4 GHZ or 3.0 Ghz.
So is it better to get SINGLE p4Xeon 3.0 GHZ ?
Or DUAL P4Xeon 2.4 GHZ ?

1GB DDR 266mhz Registered SDRAM minimum, 2 GB Maximum.

15,000 RPM SCSI HDD 73GB OR two 36 GB SCSI Drives set up with RAID. But I'm not sure which one and whether it would increase performance or not.

OR should I go with OPTERON ? Maybe will cost too much ...

2) Would you recommend cPANEL or PLESK 7 ? (new version of plesk ... looking pretty good).
The above are the OS's I am willing to use, I don't want to touch RedHat or Fedora.

3) Amount of USERS / LOAD:

I am not sure how much load I will be getting, however I am aiming at offering Shared Hosting accounts on the machine.
I want to be sure that if I end up hosting 1000 users that all will run smoothly.

One of the websites hosted on this server, is going to be a very large online community with approximately 10,000 users.

So I would like to know what settings I need for APACHE to run well etc. or does cPANEL / PLESK set things up appropriately depending on traffic conditions ?

I'm trying not to spend too much, the price gap between Xeon 2.4 and 3.0 is quite hefty, which is why I was considering doing Dual Processor 2.4 or 2.0 even.

Thank you for your time.