I used expresspcb
for one board design. Where it is really limited is the lack of rubberbanding - and being able to visualize component interconnects is key to component placement and a board that can ultimately be routable. Also, it does not have any autorouting. Or linked schematic symbols and parts symbols. After that initial design, I have only used it for quick schematics here for discussion and for documenting component placements on wirewrap boards.
After that initial PCB, All my designs have been done using eagle. Here are just a few:
http://www.crossroadsfencing.com/BobuinoRev17/
I've tried to fit things into 3 basic sizes:
50x50mm for one PCB price point with iteadstudio, ($9.90 for 10 boards)
80x100mm for free eagle size limit, and also the size of Velleman ECS 1/2 protoboards,
and 100x100mm for the next PCB price point ($24.90 for 10 boards).
Bigger than that, the price starts to increase a lot, to like $48 for 5 boards for Mega Screw Shield size boards.