I mentioned before that I was going to look into making screen rotation a tad easier for me on my Vista tablet and it seems my job was pretty simple. At first glance, I didn't notice this, but each section's icon in Windows Mobility Center is actually a link to corresponding options.
The screen rotation section brings up the Tablet PC Settings dialog. This dialog comes with two key tabs: Display and Buttons. In the Display tab, you can set the sequence you want screen orientations to rotate in. I only care about one landscape and one portait, so I disable the other two.
The Buttons tab is the important one here, tho. Here, you can change what the tablet buttons do. One of the options is Change display orientation. The one annoyance here is that you have to set it for each of the four possible orientations: primary and secondary landscape and portrait.
Despite my annoyance, I'm now a button click away from my rotation. I love it! Granted, automatic screen rotation would be better, but I had issues with Toshiba's driver before and I think I like this option better. We'll see how it works out.