Super size your antenna. I find Radio Shacks antenna to be fine. I am using the uhf/vhf combo antenna. Bear in mind that once digital tv air wave allocations become finalize, HD broadcast may come down into the vhf realm. Network would like to keep their vhf numbers.
Next get a high quality mast preamp/amp. also get a high quality indoor distribution amp. I find that digital signals are finicky and most digital tv need a strong signal to lock in. Airplanes can wreck havic on digital drop outs.
Use good quality RG6 cables that have been swept tested to 3ghz. Do not need Quad RG6. Use quality connectors and splitters (at least 1ghz).
Also consider a rotor. I prefer the remote control ones. Helps in fine tuning.
Once you go digital, there is no turning back. OTA digital is far superior to satelite and cable.
I bought a UHF from Radio Shack for under 20.00. If the channel allocation changes to VHF then it's not a big deal to swap it out. As it is there is some kind of automatic labeling for at least a couple of the stations. For example my ABC station is Channel 44 but the tuner shows as 9-1. Not sure what that is exactly.
Anyways, if your signal is strong and your transmission towers are not scattered you could probably get away with a fixed position. The towers in my area are due east and due south, so I just pointed the antenna between the two and get everything!