Yup, the PC-AT keyboard has the one true enter key in the large reverse L shape. After that things went downhill: the US layout for the Model M chopped off the top part and made Enter a thin horizontal line like Shift, and the international or ISO layout (which I normally use) chopped off the left hand part and left Enter as a rectangle: better than the US version, but still too small for one of the most frequently used keys on the board.
The biggest annoyance with the AT keyboard is the lack of F11 and F12 keys, if your applications use those (e.g. to step into statements in a debugger). The Esc key being on the numeric keypad is also odd but you get used to that.
There's also the 122-key Model F 'aircraft carrier', which has a much more modern layout, close to the international Model M layout.
But if you do prefer the US Model M layout (de gustibus non est disputandum, after all), then here's a way to modify the PC-AT keyboard: http://geekhack.org/index.php?...