When I got my DS and M3 thats about all I really wanted on it was NHL 94, well aside from the DS and GBS games. I am yet to try a Gens emulator but I'll try and fire one up in the next few days and report back.
You have a flashcart currently or is this your first? The ability to play music, watch movies, view pictures and play tons and tons of games is awesome. Throw on Blades of Steel for shits and giggles or the equally timeless Ice Hockey with the Fat, Medium and Skinny guys.