After my old PC popped its clogs, I needed to recover some data from the HD's that were in it. I was originally thinking of getting some sort of caddy, but then found this...
http://www.ebuyer.com/product/143274
This thing is great. I plugged in the drive, powered up, plugged in the USB and hey presto - instant disk based gratification! Data transfer was pretty quick (>10MB/s) too. No faffing around mounting in a caddy, just plug it in and go. Fantastic.
Haven't tried it with DVDROM/CDROM/RW drives yet, but no reasons to think it won't work.
It supports 3.5" and 2.5" IDE, and also SATA.
Not bad for £12.35!