The D-Arc. Then again, the originals have neat designs as well and have the nostalgia factor going for them, so it's close. The iC is a bit bulky, the Xros Loader has way too much going on (though I am ridiculously fond of the DigiXros stock sequences where Taiki MOVES THE WHEEL WITH HIS THUMB OMG), and the D-3 and D-Scanner seem kind of lopsided to me. Maybe I just like symmetry. I know there are various other models in the manga, but I can't be bothered to look them up right now. And wouldn't appreciate their full level of coolness anyway.
Day 02: Favourite character.
Day 03: Which digivice do you like best?
Day 04: Favourite digital monster.
Day 05: Favourite crest.
Day 06: A couple you wish existed.
Day 07: A couple you can’t stand.
Day 08: Favourite couple.
Day 09: Favourite friendship.
Day 10: Favourite season.
Day 11: Who do you think wore the goggles best?
Day 12: Least favourite digital monster.
Day 13: Least favourite character.
Day 14: Least favourite season.
Day 15: A character you’d be best friends with.
Day 16: A character you would not get along with.
Day 17: Best dressed character.
Day 18: Worst dressed character.
Day 19: A moment that made you happy.
Day 20: A moment that made you sad.
Day 21: A moment that made you angry.
Day 22: Favourite villain.
Day 23: Lease favourite villain.
Day 24: Favourite minor character.
Day 25: Favourite episode.
Day 26: What crest would you have?
Day 27: Would you ever have a Digimon for a pet?
Day 28: English names vs Japanese names (Which do you prefer?).
Day 29: Favourite quote.
Day 30: An unpopular opinion.