Looks like the only officially approved disk at this time is the WD Caviar Special Edition, WD600JB/800JB/1000JB. I'm sure that others have been used, and hopefully users will pipe up saying what they are- but that's the party line from Fostex.
I've successfully used many non-approved drives in my D1624s, but they have much lower bandwidth requirements. Let's see what the rest of the folks have to say...
They used to list other drives, and ship recorders with other drives. I don't know if it's because of availability or problems they were dropped from the list. Some from past official lists for the D2424 and D2424LV were :
Fireball Plus LM (QUANTUM) (high-speed type) 10 to 30 GB
Quantum Fireball Plus AS 10 to 60 GB
Maxtor D540X-4K 40 GB ( this is what mine shipped with )