Depends, I prefer taking my own because I'm confident in my abilities and I know exactly what I'm after. It's good to have other professionals to bounce ideas off and get different perspectives though.
@LETSMAKEART you are definitely not wrong about most designers taking hipster street shots haha (I probably fit into that category)
I also think a lot of people think because they have a digital slr that it instantly means they can also take good photos which is quite frustrating although for you @LETSMAKEART you obviously don't fit into that category as your photos are really really good
Pretty much I'll only do really really basic photography and anything else I'll either source stock photography or arrange a professional photographer
For small jobs or things that don't require close scrutiny I do my own. I often use my photos from my library to use in projects. This one for Nature Valley is a good example. http://wheresyours.co.nz/ - Mine's the photo in the background!