Jon,
I'm a little biased due to my connection to the tests, but I think you'll find the Kaplan full lengths excellent. Don't neglect the section tests, though, which are also extremely well written.
I'd suggest working backwards on the full lengths. We add new full lengths every year, and so though you'll get a lot out of every test, the most recent ones (highest-numbered ones) are the cutting edge of our research into the Verbal section.
Having a few passages in online full length #11, I'm rather partial to that one, but you can't go wrong whatever ones you do, so long as you spend a lot of time on explanations and understanding question structure. Pay particular attention to mastering Inference questions--they're the foundation of the section.