The Nokia 5800 has just gotten its v30 firmware update (actually v30.0.011). It's currently available Over The Air (*#0000# from the home screen) for some product codes, including my APAC one, as
a 4MB download. Perhaps not the 'mega' update that many people had thought was coming, tying in with the upcoming 5530 XpressMusic, this is still a recommended update, bringing bug fixes and performance optimisations.
Do a backup of your data before the update, just in case, but the User Data Preservation system should mean that all your data, apps and settings will work properly after the update.
Do please comment if you spot anything that's actually added.
[Some people are reporting that there's now an email plug-in for the (shortcuts) home screen but (anecdotally) a full/hard reset is needed to reveal it..... (hey, I'm not hard resetting mine!)]