I've bought too many dvds in my time. And the sad thing is, I plan to buy so much more, especially when I upgrade to Blu-Ray in November. There will be some replaced dvds in my future (and why I'm holding off on buying Cap, Thor, Machete and Pulp Fiction).
Movies are so overpriced, unless you can find them in a bargain bin, that I go the torrent route or NetFlix. I mean, if I like it, I have no problem buying the DVD. But on newer stuff that I don't know enough about, I just can't bring myself to buy it. If I get home, and it sucks, I'm pissed about buying it.
I might get a crappy copy online, but it's usually enough to gauge whether I would like a retail copy or not. I don't have tons of money, so the internet is often my best friend with newer movies.