In terms of time, yes, 190.53 was released after 195.22, but it doesn't have all of the same stuff. We use a branched development model, so new features went into the 195.* releases that were not ported to 190.*. As you noted, 190.53 has some of the fixes that showed up in 195.22 first, but not everything, so it's not really possible to say that one or the other is "latest". It's best to think of 190.* as a stable release series and 195.* as a testing ground for new features. Refer to the NVIDIA_ChangeLog file that gets installed to /usr/share/doc/NVIDIA_GLX-1.0/ for a list of the changes that were included in a particular release.
As for VDPAU, the wrapper library shipped with the driver is essentially just a build of the packages from here: http://people.freedesktop.org/~aplattner/vdpau/
[or in git
]. At some point, we plan to stop shipping the wrapper and trace libraries in the .run package and ship only libvdpau_nvidia, relying on the distribution to provide libvdpau itself.