I've been using raw to do a lot of the things that some people do in LR. When you make changes in Raw you don't actually change your photo it creates an XML file that stores what changes you asked for (xml files are very small). Those changes are also reversable. I did download the free beta version of LR and while it had some of the newer features (that I would have if I had CS4) I struggled working with it. I haven't been using Raw that long, but I guess I've found my groove with it. I've found that most of the time the changes I made in Raw are enough and I don't need to get a separate DNG or PSD or PNG file saving that much needed space. Raw allows you to save as DNG, PSD and PNG if you want to. I did get a book
Raw 101 from Amazon that was very helpful and gave you all the steps. I should probably do the same for LR to figure out what I'm missing or just get comfortable with it.