G, H is where I'm currently at. Would rather just use something a ton more intuitive (wheel) and leave G open as a logical 'Grid Snap On/Off' function.
Thanks for all the suggestions guys. I already have a mouse similar to the one that was listed, so will see how that goes. Bernhard linked me to a recent thread on Cubase.net where a few users were asking for mousewheel zooming. I was astounded that after all these years, they haven't implemented it, or at least the option to assign it yourself!
@Fragle: I already have PTLE. Great for editing, but crap interface (mbox), can't use my Multiface, and would be subject to LE's limitations when mixing. In a perfect world I would have HD, but even then Digi's horrid WMD drivers wouldn't let me use their interfaces outside of ProTools in any stable fashion. The RME has been one of the most rock solid pieces of kit I've ever had. Amazingly good drivers and performance. I'm totally sold on em.