As my mind wandered poolside the other day, I came across the most charming swim trunks by Vilebrequin over at Wilkes Bashford. Soft and nicely weathered-looking, they come in at least a dozen adorable retro/modern/whimsical prints, as well as a choice of lengths. It was almost too hard to pick just one pair, but I have to say it's easier for me to buy a swimsuit for someone other than myself!
If you're shopping online, Valebrequins are also at Neiman-Marcus - they even have matching father-son swim trunks - as well as the Vilebrequin online store. (Maybe because they're French, be sure to double-check the size chart before buying and plan to size up.)