I’m tired of the crappy old manual that is built for 2.5 or older versions. It is nearly useless and doesn’t actually give you instructions about how to do this and that.
I learned Blender’s interesting features thanks to Andrew Price.
It is also available under the Help menu of any official release.
Help\Manual
The 2.6 version isn’t any better, really. The manual isn’t too good in many areas, because writing good documentation is hard (and tedious). Most active developers probably don’t even know much about those orphaned areas and users tend to just upload videos to YouTube instead of writing things up.
It would be best to investigate how to automatically generate useful documentation out of user complaints, maybe file a feature request for that on the bug tracker.
An anti-manual? “To not select an object, click the left mouse button…”
And when you get awesome at blender, you can also help write a non-useless manual! 
http://wiki.blender.org/index.php/Meta:Guides/Writer_Guide
http://wiki.blender.org/index.php/Meta:Guides/Style_Guide
Happy Wiki-ing!
Right. Like all the other people who got really good at Blender over the years.