The question is, is it Takeru or Daisuke? Well, here are some answers:
Well, this is what most people believe in and so do I. There is a lot of evidence towards this couple. For example, they have a lot in common, have brothers, same digimon, in 02 together. Also in Piedmon's Last Jest, Sora said that TK was the only one to protect Kari, what is that suppost to mean? Also when Kari got sick, TK never left her side. In 02, in My Master's Voice, TK admitted that he cared for her and Kari cares for him. Also have a stronger relationship in 02, Daisuke has a crush on her but she sides with TK and when the Digimon Emperor brought out Tyrananmon and TK was protecting her, blamed himself for leaving Kari in the Digital World.
Some people don't think this might happen but here are some hints. They are in season 2 together, Daisuke has a crush on her, in the first episode, Daisuke got jealous, when TK sat beside Kari and thinks TK is making a move, got excited that Kari was in his class, Kari said he was cute when Tai gave him, his goggles, when Kari was talking with TK, Daisuke thought that he was hitting on *his* girl, when Kari was in trouble, he used his courage to protect her(isn't that romantic?), said that Kari was perfect and in the third episode, he thought that Kari was afraid and wanted to hold her hand, Use a double-sided coin, so he could save Kari and TK will wait outside.