Building a RAID

Hi
Ive decided to build a RAID 5 since Im getting tired of burning dvds. I dont really care about the speed as much as the redundancy since I've lost hard disks before. I want to build it with about 4 or 5 disks. My entire system will not be the raid, just some drives, and not my boot drive.

My question is should I be looking at buying a separate raid card, and is there one you recommend, or is an onboard raid card on a motherboard fine?
If onboard is fine, I have to buy a new socket 75 motherboard anyway (since my current one is dead, is there any one that you recommend?)

I have always had good luck with the Promise RAID cards. Also, don't cheap-out on the power supply, and use a UPS if you can afford it. Promise RAID cards make this simple. As well as adaquate power ensure you have good ventilation in your case, six drives spinning all the time generate a lot of heat. If you haven't got a MB yet I've heard good things about the intel on board raid solutions but I don't think they support more than 4 disks, something to check into though.