Need some help.

Until recently, I thought my plane identification techniques were pretty good. Now that the A319 and A320 have become a mainstay of United, I think I am back to square 1 in identifiying different types of planes.

Here's what I know so far (or think is correct):

717 - never seen
727 - third engine
737 -
747 - duh, upper deck & 4 engines
757 - long and narrow
767 -
777 - it's big
A319 -
A320 -
MD-80 - engines in back
MD-11 - three engines

Can people help fill in the blanks (and even elaborate on my comments). I'm trying to develop a mental cheat-sheet so that when I see a plane, I will know what it is.

Thanks.