Yeah, about Jack, you should really take Kelly's advice.
I just finished Mass Effect. Saved Wrex, saved the council, didn't romance anyone .. probably other stuff I'm forgetting, but this is the most important stuff.
But anyway, Tali's romance was so well developed. Slowly. Over the course of two games, if you want to look at it that way. Finding the recordings on Haestrom was probably the most memorable moment.