Are all hard disks suitable for external enclosure?

I'm looking at replacing the actual disk in my external hard disk (USB) with one with higher storage capacity. Based on the connectors, it seems to take any 3.5 SATA drive, but I wonder if all disks are equally suitable. I could imagine that some disks might need more cooling than the tight, fanless enclosure provides, or need more power than it gets through the enclosure, etc.

So, my questions is, can I just use any 3.5 SATA drive, or if not what do I need to look out for?

Generally speaking, any "Green" drive tends to work well in external enclosures. Unless the enclosure has decent ventilation and an active fan (not too loud), I'd go with a 5400 RPM drive rated for better power conservation. In the larger sizes it'll still be faster than a smaller higher RPM drive. A 5400 1.5TB drive will generally be faster than a <500GB 7200RPM drive.

Honestly, the only time I'd consider a higher RPM drive is if I were using a NAS storage device for iSCSI or heavy network traffic (More than say 5 active users). If you have special needs, like video recording then there are drives geared towards that, but it really depends on your enclosure.

You can in theory use any SATA drive if your enclosure supports changing the drive: Those connectors are standard and identical to those in your PC. That said, if you notice any drive that runs excessively hot (I have a 500GB WD Caviar that does), I would exercise caution.

If it doesn't support changing the drive, I'd just buy a new one to be safe because (a) You will void your warranty, and (b) You don't know what assumptions it's firmware makes.