Windows Phone Thoughts: What's Most Important in Your Next Pocket PC?

I was thinking about the next generation of devices, and what they'll bring, and it made me wonder what the single most important thing in the device was. Battery life? Speed? Small size/weight? Wireless? Pick the most important thing to you from the list below when considering the purchase of your next Pocket PC (whether that be from the current crop of devices or a next-generation device). This list may not be complete, so if I'm missing your #1 need, let me know in the comments.