What is your recommended Banner/Slider module for D7?
I have used Views Slideshow a couple of times and it was quite easy to use. It's based on the jQuery Cycle Plugin. The port to D7 is in alpha, so you might want to give it a go and contribute back to help the module reach a stable state.

That said, a module is not strictly necessary to do things like this. It's surprisingly easy to implement the (well documented) jQuery Cycle Plugin yourself, directly from your theme. Just add the plugin and write about 10 lines of jQuery in a custom .js file.