RAID w/ motherboard RAID controller

Read very carefully in descriptions of the mobos you consider exactly which northbridge and southbridge chips are used on the mobo. Then go to the chipset manufacturers' websites, particularly the southbrige chip that controls hard drives. SOME mobo chipset makers will give guarantees that they will NOT change the way their chips handle RAID systems. In those cases they claim that any later chipset they make that is built into a new mobo will always be able to handle hard drives from a RAID set originally written by an earleir chipset from the same maker. This would make your job in the future (replacing a dead mobo) somewhat easier. Of course, you would want a large well-known and stable chipset manufacturer for this.

I did this once already. I deliberately chose a mobo that used an nVidia chipset because they made such statements on their website. Less than two years later the mobo failed and I bought one but a different manufacturer but with a newer nVidia chipset, and it just worked perfectly! So, one success story from a sample of one situation.