Since I updated to Lion (which is a piece of crap, btw), my disk usage is intermittently at top (~10mn per hour, which is huge and kills my nice 7h battery...). After doing some research, I discovered the "opensnoop" Mac OS Utility. When I've launched it, I've found out that this Hard Drive Activity was in fact due to Dock process, which scans my Applications folder over and over, by alphabetical order.
I think it may be because of the Launchpad, which is part of the Dock process. In this case, how could I avoid it (or disable the Launchpad...) ?