Yeah I do. I'm fortunate enough to have a 32gb version, so space is ok. But I only listen to it at work, and switch to smth more portable (my Samsung mobile phone or my iPod Touch) when I'm out.
I listen to a lot of music at work and dont want to drain my phone battery too fast, so that's a good workaround. Plus I also use my iPad for other stuff at work, so the all-in-one approach makes sense...