Boxers. This "support" thing that people keep going on about with briefs and boxer briefs is something I want no part of. It makes me feel itchy and I have to constantly make adjustments. As much as I like touching my dangly bits, there's a time and a place, and I'd prefer if it's not constantly and everywhere.
Going Kommander is also an option. It's like going commando, but also involves not wearing pants.