Since I got a Tivo I've pretty much got out of the habit of channel-surfing. It's actually decreased my TV-watching significantly, as I choose what to watch and watch that, rather than looking about for what takes my fancy at the time. On the one hand that means I watch less TV, leaving more time for other things (hurrah for LJ!), but on the other it means that I don't always pick up on new cool TV that I might have bumped into by accident. Not that I ever bumped into that much - I got into most good TV late (Babylon 5 season 2, Buffy Season 3 and West Wing last year for instance).
When I watch TV I mostly
turn it on, watch the program I want to watch, turn it off
turn it on, channel hop until I find something I want watch and watch that (repeat as necessary)
turn it on, watch the program I want to watch, then channel hop for something new
visit a friend's house - I don't have a TV of my own