"Five" seems to be a big number these days - is it compression to have a "top-5" instead of a "top-ten"? 🙂 Over at Network world they've posted a quick slide deck of "Five things we love about SQL Server R2". They even include...the Start Menu? OK - I guess everyone has different likes and dislikes. I think they're happy that we gave SQL Server 2008 R2 it's own menu area, rather than lumping it in with SQL Server 2008 (you're welcome).
I agree with their first four for sure - and I'll throw in there things that you might not see as often, like being able to connect to SQL Azure from SQL Server Management Studio, increased database sizes in SQL Server Express, just to name a couple. By the way - if you haven't rushed over to check out the resources we have for you to learn the tech for SQL Server 2008 R2, what are you waiting for? They're free! Enjoy.