I'm definitely in the 'content before price' bracket. I download free books if they look interesting and I will read them all, in time! I've discovered several new authors whose works I've then gone on to buy - authors who I wouldn't normally have tried had the first offering not been free. Having said that, some of the free books have been particularly dire in their formatting (especially the early pdf's) which has made me shelve the book instantly!
It's very true what someone said earlier about intrinsic value, but it would be a great shame if new authors were intimidated from providing free product because they thought readers would think it valueless.
I find that I read books I've purchased almost as soon as they hit the reader - probably because I've made an effort to find that particular book, but also because I feel I need to read it in case there's a technical glitch and it disappears!!