Don't get me wrong, I LOVE Instant Search in Vista and I'm using it more and more to speed up my access to application, files and more. Once you get used to search - for documents in particular - you'll me amazed at how much crap you still store on your PC. Or maybe that's just me :)
Regardless, I still miss the Run command from the Start Menu and in case you do too, you can add it back with a right click on the taskbar, choose properties and then select Start Menu and click on Customize. Down ye old list there you'll find the following
Click on Run and there you have it.