Using Drupal 7 with APC, Varnish and Memcache, what bins to put in which cache?
Looks ok to me.

What you can try is play around with Memcache options. There is for example a compression flag but it usally depends on the site if it makes sense to enable it because you then have a higher cpu usage to do the compression/decompression.

I also think that page_cache_invoke_hooks flag is not necessary anymore, see http://drupal.org/node/804864. If you don't need those hooks to run then you can set it, but it's not necessary anymore for Varnish to work.

Using APC cache with multiple webservers means that you run into inconsistencies when clearing caches on one server, so if you do have multiple ones, you probably want to use Memcache for cache and cache_bootstrap as well. I've also had stability issues when using APC cache but I did use it for all caches, which might have been the issue.