Jackson's Paco Collar is his 'everyday' collar pretty much. But they're pricey, not sure what you're willing to spend. It wouldn't be my first choice for water-related activities but lots have them hold up well apparently.
(I have this one in tan/brass, and I LOVE this collar. I have never been happier with a collar. Only thing that sucks is the tan has darkened up a bit, since it's been used practically every day, out in sun, it's gotten wet a few times, etc, but still amazingly soft).
When he's going to be swimming in the pool, he wears his Kong collars from Petsmart. I also just got a vegan from Ella's Lead that we haven't tried out yet. I really like the Kong products though, and you can get them at Petsmart. They're plain, but still cool looking, IMO, and great for outdoor activities and getting dirty.
Besides leather, I really like Up Country collars. I only have one but I've seen others and really like the quality, and the cute designs.
Oh check out Cali Girl Collars as well. Cheaper than a lot of other leather sites, but great quality! We have one collar, and he just never wears it because it's not tapered at the buckle, I should've gotten it. I've heard good things about Karma Collars as well.