Just try and keep up with all the new Google Maps hacks. Come on, I dare you. I’m so far behind it’s ridiculous; Google Maps Mania, on the other hand, is doing a first-rate job. (It helps that they’re specialized; I’m trying to cover the whole gamut, and I have to make sure that the the non-Google Maps stuff gets a little room.)
If you’d like to see hacks listed in a directory, though, have a look at GMDir (thanks, Roberto).