I want to find a good HD antenna for my tv

Go to http://www.antennaweb.org/Address.aspx to get a vague sense of how strong signals are where you live--to know if you can get by with a smallish UHF antenna or you need something like I have, a DB4-size. As a comparison, I can easily get all channels they list as "Blue" and some that are "Violet" with an Antennas Direct DB4 plus pre-amp since I have my antenna in my 2nd floor with a coax running to my basement (the current model, http://www.amazon.com/exec/obidos/ASIN/B0074H3IU6/metafilter-20/ref=nosim/.) As another note, most "HD" antennas are only UHF since the majority of HD channels are now broadcast at actual channel 14 and above (the channel your TV shows and TV stations advertise might not be what their RF channel is). So, if you see, on Antenna Web or similar, lots of channels with "RF Channel" at 13 or below, you may need to buy an additional VHF antenna depending on the HD antenna you buy and their signal strength. It's not as bad as audiophile stuff, but there's a lot of snake oil about TV reception out there. But it is still worth reading around. Amps can't really help too much--they can just make it possible to do longer cable runs or help if your TV has a crappy tuner. A bigger antenna, better placement (higher/not behind metal bars/etc), and more accurate orientations are things that actually help.

Also checkout http://www.tvfool.com/ for an alternate determination of how strong the signals are near you, and which direction you have to point an antenna. VHF Real (RF) channels 2-13 (not the virtual channel numbers) are further split into VHF LO 2-6 and VHF HI 7-13. If you have the misfortune to live somewhere(like philly) that uses VHF LO you need to double check that an antenna supports it. Most are UHF only (14+), more are VHF HI + UHF, and usually only old style large roof antennas handle VHF-LO. Rabbit ears might work for VHF, but they never worked well for me.

2nding birdherder - I live in Arlington, MA, which puts me about 8 miles from most of the Boston broadcast towers, and I get all the local stations just fine with a pretty junky rabbit-ears-style setup. The thing about digital signals is, if you get them at all, you pretty much get them perfectly - there are no ghosts or other artifacts. So a "good enough" antenna is ... good enough.

Check out http://www.instructables.com/, and search for HDTV antenna--there are some really simple DIY HDTV antennas, if you like that kind of thing.

I just did this. I have a Mohu Leaf. I live in Brooklyn on a third floor apartment. When I first taped it to the wall like they instructed I got about 6 channels. When I went to move it to see if I could get better reception in another location, I accidentally dropped it behind the dresser where the tv is located and thought, eh, let's see what that does. I got 47 channels. Works fine.

The Wirecutter likes the http://thewirecutter.com/reviews/best-hdtv-antenna-c2-clearstream/

Thanks everyone for the advice, I appreciate it!

Before I went back to cable I tried all kinds antennas, both store-bought and DIY and http://lifehacker.com/5829379/make-your-own-hdtv-antenna-using-aluminum-foil-and-cardboard was the best one by far. Bonus: I bought the balun adapter at the 99-cent store, bringing the total cost to...99 cents.