AntennaWeb is another good site to see what kind of antenna you need. There is no such thing as an HD antenna. The same old antennas from rabbit ears to the rooftop monsters work. There will still be UHF and VHF so the safe bet is to get one that does both.
Antennaweb is OK but is a bit inaccurate. There are often stations you will be able to receive that are not listed on antennaweb. You are right about there being no such thing as an HD antenna. But you definitely don't want to follow the "safe bet" and get an antenna that will handle all the frequencies. Most digital TV signals after the transition will be on UHF, and if you are in an area where all the stations will be UHF you can use a much smaller antenna. There are quite a few stations that will be on VHF-hi (channels 7-13) and for those you need an appropriate antenna. There are several new antennas designed just for channel 7 and above and although because they are VHF/UHF they are larger than the UHF only antennas, they are still smaller (narrower) than traditional all-band antennas. If you are unlucky enough to be in one of the areas where a station has decided to move back to their VHF-lo frequency (2-6) then you will need a traditional multiband antenna, which are much larger than either the UHF or UHF/VHF-hi antennas.
Both antennaweb and TVfool give you information that will help you get the correct antenna. If your stations are anything but "yellow" on antennaweb then your chances of getting decent reception with any indoor antenna are not good. there are lots of very poor indoor antennas around, particularly those that don't look like antennas or that have heavy amplification. If your stations are "yellow" on antennaweb, try the Philips/Zenith Silver Sensor HDTV1 for UHF - if you have VHF as well, the Terk HDTVi is a clone of the Silver Sensor but with "rabbit ears" for VHF. Make sure you try the unamplified versions.
For outside antennas, there are lots of options. The best price-performance are probably the CM "bowties" (CM4220/1/8) for UHF (the CM4228 does well for VHF-hi also if the signals are strong) , also the Antennas Direct 91XG for distant UHF. If you want a UHF/VHF-hi combo the new Winegard range (HD769x) are excellent. If you have to have VHF-lo as well, use the Winegard HD708x range.
Just like for indoor antennas, if an outside antenna does not look like an antenna it is almost certainly an underperformer for the price. Antenna physics is the same now as it was 50 years ago. The CM4228 which is one of the two best-performing UHF antennas has been around for a very long time. So things that look like dishes, saucers, electric heaters and so on should be avoided!