I've had my Pro for about a week. I turn it off and plug the charger in every night. When I get to work (about 8:30), I turn the Pro on - it connects to my work wifi. I've turned Bluetooth off. While I don't use the Pro as my primary PC at work (our IT dept is not yet letting Window 8 devices thru our firewall). I do take it to 2 - 3 meetings everyday - using OneNote to take notes, I check personal email, browse the web at lunch, maybe draft a powerpoint slide deck. With all that, I usually plug in the charger around 3:00 - not necessarily because the battery is super low - but I like to have it charged. When I get home, I may use it off and on for a couple hours - but I leave it on - even if I don't use it. And there appears to be plenty of charge left when I turn it off and start the process all over again.
Any opinions - since I bought the MS extended 2-year warranty, my thought is that I will charge the battery whenever I feel like I need to - ignoring what is good/bad for battery life. My thought is if the battery goes bad or tends not to hold a charge very long, MS will replace it.