It's the numpad that gets me. I've lived without it for two years, but actually it's a pain not to have, especially when you get programs that use it for keyboard shortcuts, as well as just for data entry. That's why I went with the wired keyboard.
Yeah... 99 times out of 100 I'm fine with just a laptop style keyboard... but if I end up taking work home it always takes me ten times longer to do anything in Excel. Even just key combinations like shift-end-down become hard work.
That said I plan on using it for photo and video editing rather than spreadsheet work so will see how I get on (if I ever get it)