Agreed on both points !
The one vital thing to do when you get it is to check the ROM version. Start/Settings/System/Device Information. Make sure the Radio is 1.00.25.05 and the OS is 1.93.00. If not, you must consider reflashing- I suspect all current Orange Diamonds will have the new ROM, because it has been available on Orange's website for about a month now.
As to other software- it depends entirely on what you want to do. GPS needs a decent SatNav program, and music playback needs a decent player software (the Touch Player is OK, but you will soon tire of the limitations in track/album/playlist selection and navigation!)
I have found that the battery takes a much longer time to optimise than previous WM devices- mine didn't reach its full potential for about 2 weeks, though this may have been the poor initial ROM that was on mine. There's no harm in 'playing' during the initial charge, which can take up to 4 hours. Mine came 90% charged anyway.