You can have as many hard drives as there are spaces . For every IDE connector, you can have 2 devices. One is the master the other, the slave. So 2 IDE = 4 hard drives or 3 hard drives + CD, etc. You can also have 1 per SATA connector.
Guess so, do you need more room or something. BTW you can get a cd and dvd drive in one, but im not sure if they still have two ide cables going into them. Cos then u could have 3 hard drives.
Oh ok well i guess you would have to keep it like that then unless you got an external drive. BTW you would be squeezing them in pretty tight it could get pretty hot in there and you might fry one of your hard drives.