Mapping:
maps.google.com / Google Earth
www.skyvector.com has online sectional chart images.
www.runwayfinder.com lets you switch among sectionals and Google Maps views.
Aviation Destinations:
Pilot Getaways magazine
Aviator's Guide magazine
Flying Adventures magazine is another useful reference, although it is aimed more at the jet-set crowd.
www.adventurepilot.com
www.100dollarhamburger.com
150th Aero Flying Club has a nice index of airport destinations.
Fly-in Ski Destinations article from AvWeb / Northeast Weekend Flyers
There's a summary of airports restaurants here, and at flying-food.com.
Maryland's Daytripper 2007 publication covers the mid-atlantic well. 2006 version.
Pilots of America has a good message board.
Abandoned & Little-Known Airfields has great profiles of a lot of closed airports. Maybe we can help bring some of these back...
Airports and Approaches:
AOPA has a site that tells how to establish an instrument approach, and the government Airport Improvement Plan site is good, as well.
You can use this site to identify which new GPS approaches are currently being planned.