It would be nice if there was an app for my windows phone.
I agree with David. (You should listen to him--he's a well known author and technologist). :O)
Windows Phone is one of the main mobile platforms these days and if you have a serious app, you really need to have an offering on that platform. Also, from what I'm seeing, Win Phone 8 is becoming more and more the enterprise mobile platform of choice. So you'd be wise to support it to garner a number of enterprise users.
You have a great task/todo ecosystem, with cloud-backed service. And great user experiences on your client apps. (Have tried iPad/iPhone). Now to complete the experience, you just need to make the apps available on the platform that more and more of us are choosing out here.
Yes please! Windows Phone app, thanks :-)))
Followed by a Windows Desktop version.