If you're looking for a NAS with room for plenty of disks that's also fast and user-friendly, then the new Synology DS-1512+ and DS-1812+ are two models that should be on your wish list. They come equipped with the very comprehensive DSM 4.0 firmware, with space for either five or eight hard disks. You do have to reach pretty deep into your wallet for these NAS devices.
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips