Um...wow! On the one hand, not supporting a gamepad when Bioshock 1 did is rather questionable. It's also a console game, and since the console versions are using gamepads, they should be able to support them on the PC version.
On the other hand, seriously people. If you want to use a gamepad in a shooting game, spend $300 on a game system rather than $2000 on a PC. The keyboard and mouse is vastly superior over a gamepad for FPS controls. The mouse is far more precise, and the keyboard has much more functionality. In this forum thread, many people are complaining about the lack of gamepad support; some say they've even canceled their orders. In addition to the keyboard & mouse being better and consoles being cheaper, I'm sure there will be an unofficial patch re-enabling them at some point. This is almost as pathetic as the racism controversies over Left 4 Dead 2 and Resident Evil 5. Seriously guys, either use the keyboard or get a console.
2K Games (Bioshock 2's developer) stated "The decision was made early on not to support controllers at all in order to ensure that we got the mouse and keyboard control absolutely right." They also changed the HUD in order to accommodate the keyboard setup better. Now I know this isn't really a game I care about that much, but I think it's both funny and annoying when people overreact like this.