10. Kasumi Goto
As I mentioned before, Kasumi is one of the best characters in the entire series. Much like Tali, you never really see her face, side from the glistening off her eyes every once and so often. Her pale skin and lipstick always reminded me of Princess Amidala; but I felt Kasumi wore it better.
She has many sides to her—mysterious, sneaky, emotional, heartfelt—and by dabbling in little bits of each side of her, I felt she had the most layers as a character. When it came to things she was interested in, including Jacob Taylor, she was very open.. And I found that part of her a bit sexy.
As a squad member: I used Kasusmi from time-to-time, but definitely more when I played a Vanguard Shepard. Her stealth attacks helped a lot when shoved in weird corners during combat.