The new Scorpio Blue 750GB SATA hard drive from Western Digital (model WD7500BPVT, ~$120 street) is the new mac daddy in mobile hard drives, raising the bar for 9.5mm, 2.5-inch mechanisms to a massive 750GB. Previous 9.5mm high, 2.5-inch hard drives maxxed out at 640GB. The new WD drive spins at 5400 RPM and features a 3Gb/second SATA interface and 8MB of cache.
Hard drive capacity is important if you work with large audio and video files or if you're a music junkie or a data pack rat. The perfect setup in a MacBook Pro is a super-fast Solid State Drive (SSD) as your boot volume and the new 750GB WD HDD in an MCE Optibay enclosure, which is what I use.
The 750GB Scorpio Blue features:
WD also makes a 1TB notebook drive, but alas, its taller 12.5mm enclosure will only fit in the 17-inch MacBook Pro (the 13 and 15-inch MBPs require the smaller 9mm mechanisms).