I've tried a bunch of different ones even paying quite a bit for various indoor amplified ones (that didn't work very well at all) but the type that works the best for me is the type that came with the ATI HDTV Wonder. I use that one for my main TV (it's a non-amplified version) and bought an amplified version of it for my computer.
This is the amplified version. The both look the same except the base on the non-amplified one is a little smaller and doesn't include rabbit ears. I don't use the rabbit ears.
I like it b/c it's nice and small (and of course, b/c it works well