While reading a post by Scoble on WiFi being present at the SF Giants stadium, I came across seatguru.com, a site dedicated to everything related with airliner seats. You can search by airline, then load seating maps for most of their fleets, and the best part – they have color-coded the seats, so you can quickly see what seats are good, and which ones can make you feel like spam-in-a-can (movie quote, The Right Stuff).
Additionally, there is some good info on amenities, laptop power arrangements and other tidbits. In all, very recommended for frequent travellers.
My personal recommendation is to grab the seats on the emergency exits, which by law have extra room between them and the seats in front. This can give you a very comfortable extra legroom if you travel coach. In order to be able to seat next to the emergency exits, you have to assume extra duties as a passenger, mainly being able to understand instructions given to you by flight attendants (i.e. “get out!”), and lift weights of up to 50lb.
The flight attendant will brief you on these duties, and let you know that if you don’t feel like taking the responsibility, you can move to another seat. When they ask you under which two circumstances you should not open the door, the answers are: a) if you are not instructed by a flight crew member to do so, and b) when there is a fire on your side of the aircraft. Answer them correctly and you may get an extra icecream during the flight (true story!)