The Stendig 2012 Calender is the only calendar you need bother yourself with. The only one.
So if you think you know what makes a good calendar then you also know that size matters in a calendar with the Stendig measuring three feet by four feet. You can either purchase the Stendig 2012 Calender direct from Stendig for around $40 (within the continental US) or seek out a number of other online retailers.
If you do a search on Flickr for Stendig then you will see how pleasant this calendar would look where ever it is you would put it.