I almost picked Vaughn but I am such a sucker for the Sydney/Will relationship, it's not even funny! So I voted for Will.
Whoever had the bright idea to put Kendall in the mix is an SFP (seriously funny person!) Kendall and Sydney I am laughing my butt off about that one!
Despite Sydney and Kendall's occasional inability to see eye-to-eye in S2, it was interesting in S3 that he was the person she called when she woke up from her 2 year "sleep." And it's interesting that he's the person she consulted after the first 9 months of her disappearance. And then she went back to see him when she saw Vaughn and Lauren together, and it was she and Kendall who made the plans for her to work deep cover as Julia Thorne.... etc. ....
All I'm saying is that the choice to make Kendall Sydney/Julia's go-to guy was very interesting and surprising. It makes me think that despite their disagreements, Sydney always had a lot of respect for Kendall's ability to get the job done, so to speak.
I've rooted for Will in the beginning because of his caring, unconditional love for her, although S/V do have great moments as well. As for real life, Gartan all the way!!