Code Geass R1 is great, R2 is pretty crap but it's worth watching to finish the story.
Never watched Gasarki, it's on my list though.
If you haven't watched Macross or Eureka Seven by now, DO IT.
I haven't seen Macross, but i've heard of it. It's related to Robotech, right?
As for Eureka Seven, i've seen a few episodes but I can't remember anything about them, so i'll start from the beginning with that.
*sigh*
Gotta create my own list now...
Also, i'm trying to remember the name of this anime I used to watch. It was in a steampunk like setting and revolved around dog fighting in the skies. It was really cool.