You guys are actually making me consider going on what my friends call a 'burger safari'. It's a day where you eat burgers for all 3 meals (obviously you start late because you slept in- usually due to hangover- so your breakfast is actually lunch, etc).
There's this place in Seattle called the Latona Pub that makes Kobe beef burgers served on rolls from a local bakery. Probably the best burger I've ever eaten that I did not personally make-- and I make a great burger. Red Robin isn't bad.
for takeout style burgers: fatburger [http://www.fatburger.com/menu/] is pretty good, but I'm shocked that only one person has said In & Out. I haven't had a chance to eat there, but every time we go to CA, someone tries to drag my wife and I to one.
However, I have just discovered that there are two 5 Guys burgers locations in Seattle and I now have one target for the safari...