I'm using Cadsoft EAGLE and I can really recommend it.

The Schematic editor does an ERC (Electrical Rule Check) for you.
(Means you are notified if you have connected two outputs to each other, left pins floating, etc.)

There is an Autoruter included in the Package that creates the PCB from the schematic.
The PCB is cross-checked with the schematic to make sure they match.
Last but not least the Schematic Editor does a DRC (Design Rule Check) to make sure your PCB is within the specs of your PCB Manufacturer.
(Trace width, Spaces, Drill Sizes etc.)

Attached is an example of a Board designed with EAGLE
(Can't post the schematic)

CLICK HERE