WordPress MU

I looking to deploy WMPU or WP for a compnay that will have many users with subdomains for their blogs. I'm very familiar with WP and have been using it for a number of years now. I'm looking to deploy blogs with shared plugins, themes and settings. I need to be able to upgrade wp as well as the plugins on a regular basis in a single area. I don't want to go through each blog to upgrade plugins since there could be 500+ blogs all sharing the same plugins.

One major feature that's imperative to the business is the add revenue from adsense. I need to implement it through a single plugin having it show on the header, above 1st post and below 1st post. The biggest concern is deploying on all future blog sign-ups and not allowing the new blogs to modify or remove the adsense code.

Thanks in advance,
Ken

"I don't want to go through each blog to upgrade plugins since there could be 500+ blogs all sharing the same plugins."

you don't.

Since they are *shared* plugins and themes, there's only one copy of it on the server. You upgrade that, everyone sees the new copy.