I'm glad you mentioned Paine Field... Signals reflecting off planes can cause disruptions to reliable reception. Thankfully, you're not under the approach to SeaTac but you'll want to consider using an antenna or combination of antennas that's more directional than what would be needed otherwise.
I'm thinking an Antennas Direct DB4e (UHF only) and an Antennacraft Y10713 (for High VHF). Combine the two using an Antennas Direct EU385CF UHF/VHF Antenna Combiner.
There will be
plenty of signal power to drive a splitter and the HTPC tuner(s) together with the TV tuner. No amplifier needed!
http://www.amazon.com/Antennas-Direc...s=db4e+antenna
http://www.amazon.com/AntennaCraft-1...eywords=Y10713
http://www.amazon.com/Antennas-Direc.../dp/B008PBTPN4
Both antennas can mount on the same mast if they can be at least 3' apart (more is better).
I'm afraid I don't have an installer to recommend... perhaps check Angie's List?