MS student in CS meeting advisor for the first time in person (USA). What should I wear? (male) I am meeting him in his office on campus.  I am a master's student in computer science.  I figured that suit and tie would be too formal as it isn't really an interview since I already have the position.  If I were just regularly attending grad classes, I may wear T-shirt, shorts and flipflops (during the summer/fall) and jeans, polo, light jacket, sneakers during the cooler months.  Should I wear khakis, dress shoes, and a nice button down shirt?  Ties?  Yes or no?   I want to make a good first impression but not have it look like I'm trying too hard.  

In addition, he invited a few other grad students to his house for a cookout next weekend.  What should I wear to that?  I'm guessing more on the casual side but should I go in shorts/t-shirt or jeans/polo?
I've never even visited any universities in that part of the country, but I think your comfortable shorts/T-shirt should be perfect for a cookout in any part of the country.  For the first impression, make sure you choose something comfortable.  I think dress shoes would probably be overkill.  However, a short-sleeved button shirt (i.e. tailored shirt with a collar) would be a nice touch.  Do you have some sort of sports shoes?  That would be a happy medium between dress shoes and flip flops.  If not, I'd go with the dress shoes.

If you ask what food to take to the cookout, I'll chime in on that one too.