I'm rather going to persuade you into the DS "phat" as people like to call it. I'm just going to call it the DS.
At first glance the choice may be obvious: Glistening, sleek outer shell versus an awkward, ill shaped silver exterior. Smaller footprint versus a larger one, brighter screens versus duller. So whats to like here?
The DS is a no-frills gaming system. It has nothing to offer in the way of aesthetics. Instead, it prefers to just shut up and give you the games. It doesn't want you staring at its curves, it wants your eyes on its screens. Your fingers? On its incredibly responsive buttons. The DS knows you mean business, so it only brings business to the table. And its cheaper, too.
Now, the Lite? C'mon. This thing has pretentious written all over it. Yea, it may look good, and yea, the screens are brighter, but so what? We aren't trying to win beauty contests or light a room here, we're just trying to play games. The Lite can play games, to be sure, but you pay for all the extras, extras you, as a reasonable person, just don't need. It's buttons are mushy, too :'(
Conclusion: Be prudent and go phat!