Here's a good example of what sort of seatmap I would expect from a modern, for-pay service.

Key points:
1) Modern images make it clear this wasn't thrown together with some simple HTML coding in 10 minutes
2) Simple, muted color scheme makes it pleasing to the eye
3) Simple images keep the overall map de-cluttered and easy to process
4) Blazingly fast to identify occupied/empty seats
5) Clear indication of both exit rows and wing location
6) Clear distinction between seats that are taken (X) and seats that are available (color icon of empty seat)
7) More seat information is available in the sidebar by hovering over the desired seat (8C shown in this example)