That's a pretty tough question. My immediate personality traits would say I relate the most with Pinkie Pie and Fluttershy; I tend to try making people laugh, like Pinkie, but I can also being shy and introvert like the latter. However, the truh is that I find things I relate to in all six of them, as well as things I admire and respect; I can be a total nerd and obsessed with unimportant particulars like Twilight, I can be a hot head Like Dash (not much a fan of sports though xD), I've an artist vein like Rarity, and Applejack I admire her working spirit and and undying loyalty to anyone she's close too (her family and friends). Heck, even Spike in his naivity and need o prove himself, Same for Starlight's I see a little of myself into. Same goes for Starlight's obliviousness or Trixie's ego. Or Discord glifulnes into seeing the comedic suffering of others...
Yeah, as you can see, I harldy have the will to choose a favourite, because I relate to almost them all