There's fairly little choice in FPGA development software. Xilinx is what I've used, and it's easily the among the worst software I've ever encountered. But I've heard that the alternatives are no better. The fact that it works at all is no small accomplishment but it still lacks all elegance, usability, or reliability on the user end.
Those Mac OSX users, what do you use for development? The Xilinx development software seems to work only in Windows and Linux.