I work at a LFS
(mom and pop, not a chain) and I would recommend the Marineland biowheel, get the one that's rated for the 30 gallons, since they rate the filters based on flow w/o media in the filter.
Or, if you want to cheap out a bit, I've found Tetras new line of filters to work pretty well, plus they come with a little strip that supposedly tells you when to change out the filter, but I think you should do that on your own.
Don't do a UGF
, they suck. I have to clean 38 tanks a week with UGF
, and it's just a bummer.
Aqueons filters are ok too, I have one on a 29, and it does its job properly.
I think all you're really looking for is reliability and good flow. That's what distinguishes a good filter from a bad one. A HOB
filter is just a place for crap to collect, and for a bacteria-conducive environment to form.