Omar
Office 2010 released to manufacturing last week, so you would expect it to hit the shelves in a couple of months after that. Office 2007 was definitely a product launched before it's time although I get on with it fine and have done for over two years now.
The way I see 2010 is 2007 fixed! The analogy is very similar to that we had with Excel 97 and 2000. 97 broke new ground and a lot of things with it, 2000 was probably one of the most stable releases of excel ever.
You do not gain huge amounts of new functionality in 2010, web slices, sparklines, etc but customising the ribbon easily is one that everyone complained about in 2007 is now fixed.
Whatever I would say your IT guy should look at getting everyone on the same version as inevitably there are features which will not play well together if you have mixed versions and as you are only about 20% into a roll-out, it may as well be 2010.
Considering other parts of the Office suite it also means pretty much standardisation of the ribbon across the suite which was not the case with 2007 and Outlook is still adding some pretty nice features to it's armory.
Regards
Nick Hodge
Microsoft MVP, Excel
Southampton, UK