How to go about this setup (RAID 5)

Hi Community,

I have the following setup:
Abit AB9 Pro Mobo, Core Duo E6600, 4 Maxtor 160 GB drives, 1 74GB Raptor,
2GB RAM. What I am planning to do is the following:

Raptor: System drive: hold Vista Ultimate, Applications
RAID 5 using the onboard RAID and the 4 Maxtor drives for data redundancy
(poor man's RAID) to store data I want more protection for. Read/Write speeds
are less important for these.

Now how do I go best about this installation? Install Vista first without
the RAID and add the RAID later? Install all at once using the drivers
supplied by ABIT?
This is a clean install, at this point no data is to be copied.

Thanks much!