Some red T-Shirt that I don't remember where I bought it, Guess Jeans, and Armani boxers.
I don't really do ass naked, it feels weird to sit in my chair nude, but I'll chill in boxers after a shower or just sit on my towel that's wrapped around me. I don't leave my room any less than fully dressed usually, except for traveling to and from the shower (robe) and when nobody's home sometimes I'll walk out without a shirt on. I'm not one to randomly disrobe for comfort though.