Those WD enclosures are really nice, I just picked one up locally at a CompUSA that's going under for about $150 after taxes.

I think it's the first enclosure to have fans built in (at least that I've used personally), plus they have variable fan speeds depending on either heat or large file transfers (not 100% positive on which it is), plus it has a nice metal case, with alot of vent holes around the bottom/back/top of the unit for pretty decent cooling.

The power supply is an external brick, so if it does go, it shouldn't be anything tricky to replace (hopefully?)