If you're gonna be running programs... IDE.
If you are using it for storage or media, get an external enclosure. I strongly suggest the Vantec Nexstar. No fans, but sufficent cooling (unless you have a Maxtor )
While on topic, I have a HDD on an IDE controller card. It takes a long time to read when the PC boots, is there anyway to make it faster? (it is a data drive)