I would have to say that the biggest and coolest release was the NES Emulator NESTERJ! I do have a Nintendo (one of the rare ones that inserts the cartridge like a SNES. . .) but I still love the fact that I basically have a NES in my hands! Playing Mario Bros 3 and Zelda in my hands is amazing. Also I highly enjoy the release of SnesX or whatever it is. . . .
A program that I think would be great if it was improved upon would be the Calculator. If it got the decimal point and possibly pie in there as well I wouldn't mind using that baby for school!