Other than more obvious stuff like perhaps a slot 1 flash cart or a 3 in 1 for that slot 2, I was interested in knowing what other stuff you recommend for the DS.
I got:
a pouch to carry it around
USB charging cable (this is really convenient, smaller than the plug and country independent)
some screen protectors (put one on the touch screen, the protector is getting scratched, I hope the screen isn't
I'd recommend people to get screen protectors for the touch screen, and the USB charging cable as well if you travel with it. If you get a USB charger mind it's different plug for DS and DS lite!
I can't really think of any other useful stuff to get, but that's why I'm asking on a forum.
Ivo.