Using Profile Manager or OS X Server to distribute apps to a group of Macs
I have a similar setup as you are describing and use Apple's Remote Desktop (ARD) application for tasks like installing and updating apps. 
For apps that are .app files, you can use the "copy" command and move them directly to the /Applications folder (or other location like /Library/Quicktime for codecs as an example).
If the installer is a .pkg file, you can use the "install" command in ARD to have it install properly on the remote machine. 
However, for apps that have their own installer application (I'm looking at you Adobe, and your Flash updates!) you are not able to use ARD to help with this. 
Now, although this is not "automatic", you CAN schedule the time of these installs. This way you can do your updating on off hours. 
I hope this info is helpful.