I doubt you'll have much of a use for RAID at this point. RAID-0 or striping sometimes increases speeds in limited situations, but for you I'd say it's unecessary really. RAID-1 or mirroring may be even less so. I doubt you have a real need for a mirrored disk as a normal desktop user, right?
I'd either put the two 100GB drives in RAID-0 and expect very little performance gain, but at least that way you have one 200GB drive and one 250GB drive, instead of three. You can possibly fit more that way depending on the file sizes you deal with. Or just use all three alone.
As far as Windows is concerned, if you're going to use all the drives alone, you don't need any special drivers during installation, but if doing RAID from the very beginning, you may need to use an included floppy disk or downloaded floppy off the internet to install drivers along with Windows.
Which drive will be the system drive?