Jake - my daughter went abroad last year. She took a LOT of clothes (well at least more than 3 or 4 changes!). She also purchased some things there. Most of the pics I have of her and her European friends, they all look the same - jeans, lots of jeans.
Some specific "male clothes" tips that I noticed with her male friends (and I stand to be corrected by our favorite posters who actually live in Germany) - the young men wore scarves too - I mean it was cold! But they sure did look good like that. And when going out, though they might still wear jeans, they did often wear a sweater or button down shirt as opposed to a tee-shirt.
And also - with regards to the anti-American thing. My daughter was in France, a country where there is sometimes perceived to be some anti-American sentiment. She didn't have any problems, or any problems of real note. One thing that I thought worked really well for her -She made it a point, the first few weeks, to stay away from English-first-language speakers. This did 2 things - made her speak a lot of French, since it was the language that they had in common. And it made her not just one of the group of American kids - she got out of her comfort zone a little bit and it really paid off. Her best friends were from all over, only a few Americans really - and of course you are hopefully going to Germany to get a different perspective on things, not what you'd get here.
Good luck - it was the BEST thing for my daughter, something she will always treasure - I hope you have a great year.