bought an Antec MX-1 enclosure (built in fan) works great with a seagate 3.5" 1.5TB hd
left it on 24/7 for 2 yrs now, runs cool, isnt clogged with dust, stable
ended up being the same price as buying a WD/etc external
http://www.antec.com/Believe_it/prod...d=NzA0MjIxJjg0