It always amazes me how much I love Xevious (still do, it's available in one of the Jakks TV plug ins, as well as Gametap) while being completely horrid at the game. Galaga is still my all time favorite coin-op, followed by Elevator Action and Pengo.
Oh, and also this one. Loved it!
The joy of Xevious was always the music. I've found "Firepower 2000" for the SNES to be an adequate substitute...(but then again, I have the cheat codes.)