I've had the N78 for about 5 days now, and I've been highly tweaking it. I hope it comes to replace the 6300 I slept with, which witnessed my morning ablutions, which I'd forget at home once every alternate week and drive back 20 minutes to pick up. I thought my palm was permanently contoured to the sleek body of the 6300 but it seems like there is hope. The N78 ain't really waif, but that doesnt make it un-holdable at all. The buttons were particularly noticed by the bevy of ooh-ers and aaah-ers, but it is highly usable as opposed to the comments its appearance provoked. No, the buttons are fine.
The FM transistor being the main function I picked it up for works well, except a 10 second stretch on 6th ring road. I am yet to experience more than the Viva La Vida on it though. The shortcuts flustered me before pleasing me, the keypad is fantastic to navigate around once you figure out the various shortcut keys it allows you to take advantage of. My favourite standby theme hidden under the personalization feature is the Vertical icon bar that allows a maximum of about 14 shortcuts from the main page.
Another feature I found was pressing the menu key left bottom, allows you to see all open applications and go to them from there. Sheer genius. The Games required me to download NGage which works well, but I haven't found fab game options yet.... but there are many more to look through.
So thats my latest discoveries on the N78, I will certainly come back and update this when I uncover some tweaking time from my not very busy day.