EDIT
In response to the heated discussion below, it's not just the launchpad that has me a little peeved about Lion and ML (I'm on ML now). Some of things that are being taken from iOS that I don't necessarily feel belong on the desktop: natural scrolling, skeuomorphication of interfaces, suggested words, "all my files", social media integration (yes, this is just me), etc.
But my biggest pet peeve is just the sheer dumbing down of things. iTunes 11 is pretty, but why put everything a click away? What was so bad about a sidebar that makes everything instantly accessible and only takes 80px? Why does the app now prefer to be run in full screen?