The trick with stock photos is not picking the obvious choice every time and using 'as is'. A little cropping/adaptation can turn a stock photo from something obvious into something stunning. And I remember the days where a stock photo would cost £100+, these days there are so many options out there for so little money it seems daft not to play with that option.
As much as I love taking photos myself it's just not financially viable from a design point of view. If a client has the budget to hire a photographer we'll hire one, and sometimes it's absolutely necessary i.e., restaurants want photos of their food, fashion designers want photos of their clothes, (I still remember that day getting paid to hang out with professional models), otherwise it's stock all the way. Like Katedesign I wish I could take a picture of a barley field myself but I'm not going to spend half a day doing so when I can get a beautiful one from a stock site for a few quid. Most clients agree too.