RAID/HBA + Expander Recomendations

[Solarnet]

I'm looking to upgrade my server and am looking for recomendations for a RAID/HBA card and Expander setup that works good together. My MB Has 4 PCIe 16 slots with 1 Graphics card installed. The other slots run at x8. I'm using a Norco 4224 case with 24 drives (17 - 2TB, 6 - 1.5TB, 1 - 1TB - System Drive) I'm Looking for something that can handle 24 Drives with the option to expand to one of the new 24-drive DAS units later.
Must support Staggered Spin-up of the drives.

Thanks
Richard