Some BD writers and some USB2.0 enclosures don't play nice together, though you can get enclosures with USB2.0 and eSATA outputs, and if your PC has an eSATA input that might be a neat solution (it's pretty close to identical to the connnection you would have for an internal drive)
I personally prefer one with a built-in PSU, no dangling power brick, and for a removable, no fan (noise) needed. and if moved frequently, some sort of handle would be a very nice touch indeed not that I've seen any like that.
Go to Thermaltake's website. They have some refurbs at very good prices. I generally use the docks, but I have a Thermaltake Silver Duo that has both eSata and USB options and it's been very reliable (3 years old refurb and no problems). Not sure, but you may even be able to get an extra power adapter for it through them.
Wonder if I can p/u a second power brick somewhere for that so I don't have to drag the cables around but just the enclosure?
I used a blank expansion slot panel and installed a power plug in it, then soldered it to one of the PSU leads. Be aware that many/most SATA enclosures need the system powered down before connecting (for the drive to be recognised) USB doesn't have that restriction.