In reply to Emmanuelson.

I'm working on the basis that:

a) I look after lots of sites and want enhancements on all of them
b) My client has few sites and probably won't want the enhancements anyway.

There's pros and cons. You can install Toolbelt (or the plugin version of my thing) to get the same feature on a single site. Or you can install my extension (once it's ready) and have it on (almost) every WP-ADMIN you visit.