No, No, No, No, No!
No computer with a user having admin rights should ever go on your network. Certainly no company owned computer should have user admin rights:
I don't hate users, but an IT dept just can't do it's job effectively if they constantly have to fix self inflicted computer problems.
Why on earth should users (developers, if you have them, excepted) need admin access.
To install applications?
We spend a great deal of time and effort testing applications for compatibility then we standardise on a particular version. We maintain licensing information, and agree to support whatever we install.
To run apps that require Admin access?
Hey we are not running Windows 98 anymore. I can't recall a standard business app that requires admin rights. If one did we would not allow in the first place.
That's what WSUS/ASUS is for. Most users don't need the latest graphics card drivers - they are not gamers!
What if [insert reason here] had to run as admin?
Then they are totally segregated from the rest of the network, possibly if there were enough of them, in their own domain. Most importantly we manage their expectations - you break it you fix it - normal SLA resolution times don't apply.
There are lots of edge cases, but we aim to run our department so no user should ever need admin access or even request it. If your users have admin rights then you do not control your 'network' not a situation I would ever want to be in.