Ooh, interesting question for a yogi.
I love Travis but for most yoga, including his, I'd prefer a small class to a private session. (I was in a class of about 24 with Travis, which is probably the best I can hope for!)
OK, here's one -- A private session with Ana Forrest would be on my bucket list. But it would be the LAST thing on the bucket list, because it would probably kill me!
Desiree Rumbaugh is in a similar category. I did a weekend workshop with her and the alignment focus was so intense and so great. Having her focus just on me would be incredibly valuable but incredibly challenging.