Easily Mario vs. DK 3. Followed closly by MFC.

My favorite DSi game is easily Mario vs. Donkey Kong: Minis March Again. I mean it's got tons of puzzles, unlockables, a level creator and even the ability to share and download created stages via wi-fi. What more could you ask for!? To be honest i actually prefer this to it's cartridge counter part, Mario vs. Donkey Kong 2.
Runners Up:
-Mighty Flip Champs
-PiCTOBiTS
-Dr. Mario

@bboy2970
exactly. No further comment.

Of the stuff I've bought...

If price is a factor then Bird & Beans (Why is it called that, it's times like these I hate being American! But I dearly love the country so I would never leave)

If price is not a factor then AQUIA (And yes on the DSi Screen it is titled simply AQUIA, then has series info and stuff)

for me i gotta say mario vs donkey kong first then picto bits and after that dr. mario. i don't really know anything about mighty flip champs

Mario vs. Donkey Kong and Aquia.

Runners-up include Pictobits, Dr. Mario, and even MFC -- however, I personally have found MFC to be rather disappointing overall... I haven't played it once since I downloaded MvsDK, because if want to play some sort of puzzle-platforming hybrid, it just isn't even in the same league.

The web browser is great, if we're not just talking about games.

Pictobits has given me the most enjoyment so far, but I really dig Minis March Again and MFC too.

PYORO!!!! and asphalt4!!!!!

pyoro? you mean bird and beans?

mario vs donkey kong minis march again
mfc
bird and beans
paper airplane chase

pyoro? you mean bird and beans?

mario vs donkey kong minis march again
mfc
bird and beans
paper airplane chase