Second the recco for flyers'places. I believe it's meant to be a supplement to Flyertalk, not a rival. People should check it for restaurant info; for one thing, you often get better, fuller reviews than people want to post on FT.

Planebusiness, of course, is a biggie, which focuses on the business side of things (surprise) sort of, anyway. You get lots of pilots, some other airline employees, some interested pax, etc. LexPax posts there a lot. I read occasionally.

Funnily enough, one of the most recent times I was reading Planebusiness, a topic called What other boards do you read was then current there. Flyertalk got mentioned a couple times as the best "other" board. But we also get called opprobrious names by some of the planebusiness guys.

Planebusiness guys often refer to another board as "airwhiners.net" - there are other opinions of it, of varying flavors, (wasn't this discussed someplace on FT recently?) but it does at least seem a good resource for pix of planes.