Hm... well, definitely tall. Not freakishly tall, but big enough to seem like a caring, protective father figure and a generally big guy. So somewhere around 6 feet. He's not necessarily athletic, but has a high metabolism that keeps him at an average weight despite probably being a guy that eats a lot of junk food. He dons a black, scraggly beard (which Tali will come to love nuzzling against) with matching hair. Mid 20s or even early 30s, works as a store manager, lives alone at an apartment and walks to work every day. Has enough to pay rent for the cheap apartment he lives in and even has enough excess to indulge in his PC gaming and fast food habits. He has green eyes. Also, his hair and beard might look something like this, though it'd be black hair.
http://media-cache-ak0.pinimg.com/73...84048572d0.jpg
Some of those ideas sound okay?