It'd be very easy to fill all the useable drive bays.
1) Media I/O panel (case has no front audio, USB, firewire, etc)
2) Fan controller
3) DVDRW
4) CDRW
5) 1 Hard drive
Then it's full already. The lower 3.5" bays don't have enough ventilation to use for modern HDDs. Granted you dont' "need" fan controller or Media I/O panel but those are just some of the benefits of a large case. Another is being able to use two power supplies. A pair of ~$35 Sparkle 350W PSU have much higher sustained capacity than any one $70 PSU, and potentially half the heat density but twice the ventilation so they'll last longer.
This case is ripe for moddin' though, over the years when i throw out old AT cases, I take out the drive bays when they're the type with front or bottom screw-mounts (or flat tabs that could have holes drilled), because they're easily added to the bottom of a case like this then secured with a $1 pack of nuts & bolts.
This wouldn't be a very good case for someone wanting to just use it "as-is" unless all they needed was 5 5.25" bays for whatever reason, but it's clean lines give it a lot of potential for moddin'. The main limitation I see is that the rear area adjacent the I/O ports isn't wide enough on either side of the recess to add a 80mm or larger fan. Then again, there's room for a 120mm up top so I doubt there'd be any heat retention problems but with 80mm lower in rear it'd be even better.