Well, we're coming up on the end of the year for 2013. This year, the installment-purchase of a AF-S II 600mm f/4 D IF-ED lens made a major difference in my photography - allowing me to get closer to birds at the places like Serpentine Fen and Green Timbers. Also the purchase of a TC-20EIII (a 2x extender), expanded my photography focal capabilities of my 70-200mm f/2.8 VRII from 70-200mm to 140-400mm
On the list potentially for 2014 is attempting to get a Sigma 50-500mm lens (this will end up becoming my wife's birding lens) in September as well as paying off the 600mm (final payment is in May 2014). Depending on how it goes, we may be able to slip a set of Lee soft ND filters in there as well. It just depends on how much is left after the 50-500mm in September.
At least hopefully this will be what is potentially possible to get for 2014. Each purchase is an investment into my photography and hopefully, with the purchase of the 50-500mm, my wife will get as much enjoyment out of bird photography as I do with the 600mm.