Want to change the function of your Home button? It's pretty easy. As you may know, double-clicking the Home button will normally bring up your multitask pane (that's the default). However, you can change that if you'd rather it serve another purpose.
Simply go to:
Settings > General > Home
Under there, you can set your home button to do whatever task you want it to when you double-click, whether that's taking you Home, taking you to the Spotlight search, or to the iPod controls. It's interesting how many actions can be carried out with a single button. Too bad rumors say that the iPad 2 may lose it.