As for designing websites in photoshop, at work we do it in keynote. It works surprisingly well and you can use mocks for presentations too! reference -> http://blog.swixhq.com/designing-swix-with-keynote/
I'm not designer, I wouldn't even class myself as a developer, but like everyone else I have a few web projects on the go. I've been searching for a low overhead way of getting a design mock-up down and your keynote idea hits it on the head.
Really being a hacker, I just want to mock-up a design that isn't butt ugly and for the tools to get the hell out of my way so I can start cutting code.
Check out http://keynotekungfu.com/