I get quite a few emails on what to wear to the gym when you're tired of pit-stained tees from college. I prefer darker colors as they don't show any dirt or sweat marks as you workout, and slimmer fitting clothes for ease of movement. I also wear fairly short running shorts, mostly because of range of motion with lunges or leg exercises. Running shorts are also nice underneath because they have a brief inside for a little extra "stability". Here is pretty much exactly what I wear to the gym, except I have an older version of the shoes. You don't have to dress in all black, all Nike, or even as slim fitting as I do, put keep it simple, no baggy clothes, no graphics, and for the love of god retire the nasty t-shirts.