Honestly, the original DS is so much harder to see and so much less comfortable than the Lite, I have to recommend paying the extra $20 for a used Lite, even if you're just playing a few games. I really didn't like the original DS, even when it first came out, but the Lite is amazing.
The DS Phat is atleast bigger, so my hands could hold it more easier. The DS lite is too small, and the shoulder buttons suck and the speakers are lower too!