First congrats on the machine, best Amiga ever IMHO.
You can opt to use a small SATA drive in a SCSI carrier such as the Acard ARS2000. I wrote a review on it a while back here.
If you can find one, a CyberVision64 provides a really super nice high res Workbench but then you probably also want a better CPU for "the snappy" better performance. There is no limit ;-)