Hmmm.. I don't HATE anyone actually, so I'll just discuss what I like or dislike about each character in an arbitrary order.
TALI! I luffs you! And she's actually one of the few characters I could actually see being actual friends with. (The Other is Jacob) She's just an awesome and nice person all around, and one of the few who shepard doesn't have to tell constantly to stop being such a dick.
Jacob is a nice guy, there's nothing wrong with that, however because of that, he doesn't manage to be much more interesting than Kaidan(though he DOES beat him.)
Miranda... she's ....haaaaawt... I mean! uh... err... I don't really hate her personality, but she's all sad about being perfect and is cocky at the same time. I didn't like her the most but her rear end sure was puuurrty...
Hmm, it's weird, the two human love interests seem to be a lot less interesting characters, at least when compared to the other ones. However Miranda has the amazing hindquarters that make it into at least one frame in every conversation with her, and Jacob has a body so hard he could cut diamonds with it. Hmm...
Thane... I didn't get to know him much the first time, though He's kind of nice and has coat-tails, all he says ends up seeming sort of like this: Something Something Something Angsty angst Kolyat. Something Angsty Dark Something Kepril disease. Not to mention he freaked me the hell out the first time he did the Drell Memory trip.
Garrus! Garrus, how awesome you are... yet how scary... I always loved how Garrus was basically Shepard's Protoge throughout the series. However, as time goes on and on, it always seems like Garrus gets more willing to do anything for any reason he deems worth it. I can't be the only person who thought that Warden Kuril on the Purgatory Prison ship was a sort of cautionary tale of who Garrus could become...
Samara... Now that's cold. Cold as Ice. I mean, I sort of understand after you finish with her loyalty quest and everything, and she seems less cold by then. She's also pretty awesome looking. I gotta admit, when it comes to combat, Samara is a BEAST. Assault Rifles and the prrobably brokenly awesome Reave skill. There isn't much to say as far as character goes, but she is definitely top tier when it comes down to a fight.
Mordin! He is the very model of a scientist salarian! He's studied species turian, asari, AND batarian! He's so great, ever since seeing Captain Kirahe in the first game, you know you've needed a salarian character. Though sad but awesome, if he dies, he talks about how he "Held the Line" classic.
Jack, so much hatred for Jack around here. I actually really liked her. She actually had a REALLY fleshed out and developed character. There was a reason why she was the way that she was, and you knew it. I loved the scene where she finally broke down and cried. Also, her badass "matter-o-fact" attitude was one of my favorite things to hear when one of my allies had something to say.
Hmm... Grunt... okay, I take it back, there is one person I did hate, and that was Grunt. Where Wrex was interesting and wise, Grunt really seemed to just be "Angry Krogan Fellow". I would have liked to have the imperfect Krogan clone that you met in the beginning of the mission, or even Dr.Okeer, as they actually could have been interesting.
Legion was pretty cool. I was glad to have a geth member, and his first conversation was just halarious. ".....There was a hole."
And Zaeed.... eh.
Well, just some thoughts.
TL, DR: Luff Tali, screw Grunt.