Which should I buy first?

[Ryth]

Golden Sun or Advance Wars?

[Captain Maxx Power]

Advance wars. The greatest GBA game ever. Period.

[Maxico]

Thats a tricky one as they are both very good... I would say advance wars at a pinch.

[Lord Chainsaw]

I'd say Advance Wars is one of the best games on the GBA right now. If you have friends to play with, the fun is multiplied exponentially. You don't even need more than one game or GBA, just take turns passing the GBA around and making your moves. I remember Advance Wars was all we used to play in Golf class. I'd highly recommend this one.

I also wouldn't recommend Golden Sun. It's my least favorite game of any GBA game I've owned, and one of my least favorite RPGs of all time.
I can't speak for the sequel, because I got turned off by the first so much that I've never picked it up, but they might have improved that one.

[Ryth]

I planned on getting Advance Wars first but I wasn't first so I'll probably get that. Still not 100% sure though.

[XxSephirothxX]

It simply depends on your taste. If you want a brilliant RPG with incredible graphics, a great story, and a super-fun battle system, definitely buy Golden Sun. The sequel is one of my all-time favorites. However, if you prefer strategy games, Advance Wars is one of the best. It's quite addictive.

[WarZidane]

I like Golden Sun more, but Advance Wars is better. (just that i don't like that type of games that much :p)

[Erdrick Holmes]

Neither of those, buy Street Fighter Anniversary Collection.

[Ryth]

I just got Advance Wars 2 for xmas so I'm getting Golden Sun.