I've used IntelliJ for previous projects, but I am definitely going to give Eclipse a spin for the next one.
The Visual Layout Editor seems like too much goodness to miss out on. Jump to 7:17 in this video for a demo: http://www.youtube.com/watch?v=Oq05KqjXTvs
It's funny that he wrote off all the other IDEs in favour of Eclipse which requires more setup than to do Android development than IDEA does. Even if I didn't hate Eclipse it'd be hard to argue with "1. Install IntelliJ, 2. write your code".
Anyone who's used both IntelliJ and Eclipse as IDEs for Java development knows what I'm talking about. Eclipse, like Android, emphasizes "openness" and customizability while IntelliJ, like the iPhone, emphasizes "It Just Works" coherence and integrity.
If you like IntelliJ's approach, you might want to try AppCode, a development environment for Objective C made by the makers of IntelliJ, JetBrains. http://www.jetbrains.com/objc/