Scythe have made headlines today with the release of their very handy "Kama Connect" device.
This USB device allows you to connect S-ATA Drive (2.5/3.5" HDD, Optical Drive), 40-pin ATAPI Drive (2.5/3.5" HDD, Optical Drive, IDE/EIDE, ATA33/66/100/133 Ready) externally via USB port. This Kama Connect can eliminate the hassle of opening your case, unscrewing and detaching the drives to connect and use it.
You can even connect up an IDE and SATA based HDD simultaneously with it (As shown below).
For more info and images, check out Scythe's product page.