This seems to be the highest quality config I can use that gives me working videos without lag or jutter. If you're using "Constant Quality", I've only tested RF as far as 20 on moderately high-speed motion with no issues (720p). If anyone has more to contribute regarding their own settings, it'd be much appreciated. I use MVideoPlayer to watch stuff.
Note: Do NOT use MKV. For those watching anime on their Adam, I feel for you, but you'll have to include the subs separate. MKV support on Tegra 2 is straight-up buggy. On many videos, the Adam will straight-up cut out at various points, and the Xoom (also Tegra 2-based), will lose audio at the exact same points (exiting and resuming the video will "fix" this, up until the next bug-inducing moment).
Also, any "attachment" system that automatically converts PNG to JPG, even when the resulting JPG is A LARGER IMAGE SIZE (and lower quality, and a lower, unreadable resolution), needs work.