Okay a lot of the info in this thread isn't too relivent.
Corporate ipads/iphones.
Don't need itunes - there is a tool/server that you can run. It will push out apps and configs to the devices over wireless. You can disable iTunes sync if you want(iirc)! So no MP3's/music problems.
The tool or exchange 2010 has remote wipe.
I would recommend you give apple a ring and get someone from there coporate team to come and show you.
iPads and iPhones fit perfectly into what you want/need. As you can control settings/apps that are one the phones through apple supplied tools. Including things like wireless settings, exchange ect.
As mentioned above:
http://www.apple.com/iphone/business/integration/
With iOS5 there are a lot more comportate enabled options available. And iCloud being one to help.
http://images.apple.com/iphone/business/docs/iPhone_Business.pdf is a really good document to read.
Also as you are buying as a corporation you can get discounts + quicker stocking - no worring about apple stores having stock.
One guy mentioned about updating. When iOS5 comes, updating is done wirelessly anyhow - and you with the corporate software should have control over this.