DDR333 support isn't important unless you're overclocking. Dual channel DDR266 perfectly matches the bandwidth capabilities of the processor. Using DDR333 in the system would only show the negligible performance gains that you see in an Athlon system with DDR400 vs. DDR333.
I am curious as to whether Ganite Bay will include native support for SATA and firewire. Actually, SATA's the only really important thing to me. I'm hoping Shuttle will release a Granite Bay-based SFF. They added a VIA firewire chip to the integrated 845GE motherboard, so I'm sure they'd so something similar with GB if it doesn't have it already. But I'm really looking forward to the move to SATA (tiny, non-airflow-blocking cables being a big win for SFF), but I don't think Shuttle would include a third party SATA solution.