I am a huge fan of Icebreaker - once I outfitted myself right down to socks, I don't even wash my workout clothes for weeks unless they just get dirty. That being said, I don't mix them with clean clothes unless they are just laundered. Also great clothes for travel - I never get that clammy feeling during a night flight that can happen with cotton. And, lightweight.... The price tags are high but trust me, worth it. Merino wool, who'd have thought?

Icebreaker.com