There are a lot of good Mac Software Bundles this month, but none are a better buy (imo) than the ProductiveMacs software Bundle.
This includes the MUST-HAVE apps-- Default Folder X, BusyCal, Fantastical, and Notebook. There are even more apps included, but I haven't tried them -- such as Home Inventory, Tags, Launchbar, and Cashculator. Default Folder X alone is usually $34.95, and worth every penny -- so getting Notebook and BusyCal on top of that is a huge bonus.
If you already have some of these Apps, you can also Gift them to someone -- and what a Gift that would be!