While some power users my not like the new Ribbon (you can hide it), most non-power users will probably find it much easier within a couple days. I had my experiences of "how do I find this" with the ribbon, but overall very nice. Also, since the Ribbon is open for development I expect to see more function-specific or industry-specific customization in the future.
I particularly like some of the new functions when working with PivotTables. For instance, although perhaps mundane, the IFERROR provides a much more elegant solution to error-checking than an If and Iserror combo.
Finally, here's a macro snippet to 'wrap' the IFERROR function around formulas that have already been created. Very useful when working with other people's files or updating with different data.
Enjoy the increased productivity...
Sub ErrorToZero()
X = Right(ActiveCell.Formula, Len(ActiveCell.Formula) - 1)
ActiveCell.Formula = "=IFERROR(" & X & ",0)"
End Sub