I used to use mobo RAID5 and RAID1, worked awesome; i had several drives fail over the years, and each time i'd just overnight a new one from newegg, pop it in, and off it rebuilt itself. Previously I had lost 3 HDDs with DVDs on them, and had to rerip 50-100 DVDs each time. God that sucked. After the mobo RAID5, i've had 1 HDD die, but it was super-duper simple to recover and no re-ripping needed.
The token issue with RAID5 on mobo is that if the mobo dies, you're screwed. If the mobo dies with RAID1 you're ok as you can pop that into another box.
The primary reason I left mobo raid (both 1 & 5) and went to a HW card is that I wanted to exceed 2TB (mobo RAID5 doesn't allow that) and have >6 HDs (most mobo's only have 6-8 SATA slots max). I tried the "cheaper" RAID cards (ie, i have an LSI one that cost me $300 that i'm going to be eBay'ing soon), but i'm not technical enough to get it to work right. I ended up with a damn expensive 16channel Highpoint 3540 RAID card, holy crap is it fast and awesome, but it was $800. I have a 2x1TB RAID1 and a 5x1TB RAID5 on it, expandable to much more. I used WHS and created a GPT partition, so I have a single 3.8TB array (I bypassed the WHS console).
Well, now that i've typed that out you'll see that HW RAID isn't really low cost, but it is expandable and it is awesome and just works. Then again, so is mobo-level RAID, and for 99% of the populace I think the odds of a mobo dying are quite low.
I don't know squat about Vista, but I have to believe that ICH8R/9R/10R (mobo RAID) must be able to work on it, that's what i would recommend. You can even build multiple arrays up to whatever # of HDDs your mobo supports. A single 1TB boot disk, 2x1TB RAID1 for "critical data", and a 3x1TB video array gives you 3.5TB of usable space (.5TB on the boot, 1TB on RAID1, and 2TB on the RAID5).
Yes, I'm "that" Home Automation Guy.