I got my parents to buy me a DS for Christmas of 2005. A few weeks ago, I went out and bought a DS Lite! And what difference it makes.
In one of my games, when I played it on my Original DS, I thought the words were black.
On my DS Lite, I've realised the words are actually GREEN!
It's an amazing improvement, and I thoroughly suggest you get one.
P.S. A PSP in itself costs £129.99, the games cost £29.99, the memory sticks cost £19.99. A DS Lite and game costs just £129.99!