I'm probably buying MORE than I did in previous editions. Before, I might buy a class/race book if it truly interested me, but I've found that the new setup (especially the new fluff that's starting to show up since Divine Power) has me eager to purchase and read. The increased Campaign Setting release, along with the multiple DMG's hasn't hurt the flow, either. And, all that would be moot if it wasn't for the high quality of the books. DMG2 is one of the best RPG books I've ever read. MM2 was stocked with great new and old monsters.
I'm not quite to a book a month, but i'm buying more books than I ever did. Minis, on the other hand, have slowed a bit. I haven't bought them as much; considering I have almost 2,000, I really don't have a harsh need to do so.