Good tips, I knew this would be the place for concise, quick info. Without search it's hard to find that shit on gaf.
I have a DSL now, I used to have a regular DS but I traded it in for the Lite (and lost the ability to play GB carts.)
I might have to look into a flashcart for the time being, mine is acting up now (had an R4 but I'm not sure what the good card is today.)
I saw used GBA SP 101s on Amazon for about $40, will definitely look into a gamecube adapter as well for the collection. Is the Gamecube Gameboy Player better than the one that came out for SNES?
edit: I love the idea of the micro and wouldn't care about the carts sticking out, but I'm not in a position to play portable games often. I'd just as soon play a gba sp or play the games on a tv at home.