The barcode scanning for the various shopping apps is a great feature. I've noticed better battery life recently since the last major firmware update, it also may be due to me using it slightly less as the novelty has worn off a touch.
I also keep a mini USB charger for use whenever I get into the car with it. Also helps if you want to use it as a GPS in the car for any length of time.
The touch screen is good but nowhere near as sensitive as my Ipod Touch, that said it has the keypad so you don't need it other than to tap the odd menu item now and then. Using it in the few games or touch intensive apps I've tried worked fine too.
To echo some other peoples favourite Apps:
Beebplayer
sms popup
Last.fm
Chess
Compare everywhere
Doom
Missed Call (allows you to customise the colour of the LED on the front on various status messages)
PdaNet (pairs the phone with PC and uses 3G as a network connection)
Useful Switchers
VNCViewer
Wikimobile
Amongst others....
I've not rooted it yet but I hear that it's a good way to tweak battery life a little and get the most out of the handset. I'll be attempting it in the near future.
EDIT: I also wanted to say that if, like me, you use Gmail and Google Talk as your main method of electronic communication then this is the phone/OS for you.