Eagle

Autodesk's Eagle software allows professionals, makers and hobbyists to take an idea as a schematic for an electronic circuit, simulate the functioning circuit and create a printed circuit board design that can be etched and assembled.

I used to use Eagle a few years ago but then the license expired and since I was no longer a student I couldn't afford the price for another license to use the software. The free version is fine but the paid version gives a lot more options and freedom for design.