i would say get both.

NDSi

1. no need to switch on and off your NDSi during swapping games
2. DSi shop
3. Camera for casual shotting and on spot photo editing
4. Music Playback
5. Build in Internet Broswer

NDSL

1. GBA slot for pokemon to trade from ur GBA pokemon to NDS pokemon, and also games like guitar hero that need grip
2. Longer playing hours



p/s: pika, only NDSi Shop's games are region lock, normal NDS Catridge is still region free.
the power button on the ndsi is near the d pad and also very near to the bottom screen, i don't see why ur hand will reach that part because our hand is actually slide to 45-60 degree holding a hand held console, unless ur holding ur ndsl 90 degree.
and no, i support originals so, homebrew, ahem games does not concern me at all.