The Logitech Dual Action controller is a standard USB gamepad for any PC. It is one of the cheapest pads out there for the PC, and is a great value.
The controller's design is essentially a clone of the Sony Dual Shock. It uses the same assortment of four shoulder buttons, four face buttons, two analog sticks, and a D-pad in the same configuration as Sony's controller. It also includes rubberized grips on the handles.
This is the second iteration of the Dual Action that I have owned, and the current version is a big improvement. It is much heftier and more durable, and the new rubberized grips make it very comfortable. The D-Pad, which was awful in the original version, has been much improved, and actually functions competently now.
The Dual Action is very inexpensive, but it is one of the best PC gamepads I have tried, in a design that most games will already be familiar with.