The three-finger drag is completely asinine. It's a great way to completely f*ck yourself if you drag while your mouse pointer is over a file list.

It also takes one more finger to accomplish what I could already do with two before. Click and hold with my thumb while moving the window with my index finger.

The three finger navigation has always been there on my Unibody MBP (March 2009).

The inertia option is OK, but IMO, not terrible useful unless you have a really long list you want to surf through. Non-inertial scrolling already worked very well. I'm using inertia now though, at least for the week to see if I find it useful enough to keep turned on permanently.

Scrolling is what I do the most. I don't use pinch zooming as I find it imprecise and just a pain in the ass. I've had to instal mods for Mail and Safari to disable it in those apps actually. I also can't really stand the rotation. The only apps I use that support it are from Adobe, and their use of it really stinks. I may need to disable it in System Prefs.

The other things are useful, but I don't use them enough to commit them to muscle memory. I find it much quicker to Expose using the keyboard with my left hand while moving the mouse cursor at the same time with my right.