We've been rather impressed with Seagate hard drives. We still use IDE Western Digital drives (WD800BEVE, 1600BEVE, and 2500BEVE) in our E2s on account of their quietness, minimal power consumption (about 1 additional watt) and general reliability. But our new Atom PC runs on SATA-II and what's more our forthcoming E3 likely will as well.
Seagate has made some great inroads with their new 7200.3 series. Low power, a bit noisy, 7200 RPM, and 16MB Cache. It has 80MB/sec read speed and 50MB/sec write speed - that's way above CF cards and approaching SSD levels.
As they announced today in London, they're skipping the market. To quote Bill Watson, "When Samsung can't make money at this… it's a tough market."
Of course, we're happy to take advantage of loss leaders and will be announcing the Atom PC with 32GB OCZ SSD (Ubuntu or Vista) next week