Gundam Geeks And Gearheads, I Need Help!

Hey, everybody!

A friend of mine recently discovered Gundam (I haven't seen Gundam.  I 
don't know which one, assuming there's more than one series, I just know 
it's not SD).  For Christmas, I'd like to get him a Gundam game.  So I 
looked into what's available.

Holy white tornado!

So I turn to you guys--which one do I get?  Which one is the best, which 
is the worst, which is the most intriguing, follows the story, etc.?  He 
has a PS2, so the game can be the one for the PS1 or the PS2 without any 
hassle.

Dobre utka,
Pete Holland Jr.