I got a Bytecc ME-350 enclosure to with a 160 GB Samsung drive to use for external storage, USB 2.0 attached. It works very well.
Two points:
The enclosure has an on/off switch that I use when I am moving the drive from one system to another. I found that if I just did a Safe Removal from on system, then plugged the USB connector into an other system, the system would not always detect the drive. If I powered the drive/enclosure off, then turned it back on (after waiting a few seconds), the drive would be detected. I haven't noticed any ill effects from using the power switch, but I have only had the enclosure for a few weeks.
The Bytecc ME-350 has an external power adapter. On the plus side, the enclosure is nice and small (well made, by the way). Having the external power adapter may be seen by some as a negative. If you move the enclosure around a lot, it's one more thing to keep up with. One of the guys at work has an enclosure that has the power adapter built it. He only needs a standard power cord to power the enclosure, but the enclosure is bigger. It comes down to a matter of preference.