Question: I've noticed that there is a little give in my camera system at the EF mount. It is really hard to see, but I can feel it sometimes and first noticed it when I had the lens attached to a monopod and gripped the camera body. Even though I was supporting all the weight with the monopod I could still feel the body shifting around slightly. This seems to happen with my more expensive equipment and my cheaper equipment, but if there's something wrong I want to make sure I get my expensive equipment in for repairs before the warranty expires.

Thank you.

Answer: 
As long as the faces are flush together and the movement is rotational only I wouldn't worry unduly. The mechanism will have a degree of backlash to account for variations in tolerance for all the different lens manufactures since the introduction of the EOS EF mount.

However, if there is a gap between the lens mount and the body, you'd notice this with a reasonably sized lens on (70-200mm) as the weight of the lens pulls down and a gap opens at the top of the mount. This would point the to mechanism that pulls the two together is not working and that should be looked at.

If so then it will be the body that needs attentions since all your lens have the same effect.

But, personally my lens (Canon L, 'normal' and sigma) all have a little rotational play and I wouldn't be worried.
It really depends, but a very very slight movement is acceptable. It's within manufacturing error.  

You might read bit more about it here: <http://forums.dpreview.com/forums/thread/1950530> :)