I've been having a look at Moodle 2 and what problems to expect if we decide to update the live site.
Just as a heads up for anyone else thinking of updating to Moodle 2 here is a short list of issues I've come across so far;
Modules Not (yet) supported
Blocks not (yet) supported
Before importing the DB from the live site change the MyISAM Tables to InnoDB and where possible change the collation to UTF8-general_ci, it will save a lot of switching back and forth during the install process. (PhpMyAdmin is a good tool to do this)
I found that recreating our live site and updating that to Moodle 2 worked better than trying to import the DB to a clean install of Moodle 2
Please feel free to add any other problems and\or cures you come across. I've still got a lot of testing to do so may well add to the list later.
I'm running our test setup on Win 2008 Svr with the latest Apache, MySQL and Php installs.
In terms of modules not yet supported, you'd probably be better off listing modules that ARE supported - or are in the process of being updated - as the majority of contributed modules do not work in Moodle 2.0 There is a tracker entry showing which contributed modules are updated and progress on others but I haven't got the URL to hand.