Moonmadness and Mirage are the gateway albums. They sum up everything that's appealing about the band for me. If you like those, move on to the other releases, but anything after 1980 is spotty.

I personally have a thing for I Can See Your House From Here too, but a lot of that probably has to do with the memories it triggers.

You may want to try Harbor of Tears and Dust and Dreams too. Both of those have some great sections worth ripping to the shuffle.