What is it you want to do?
For schematic capture, posting something quick for the forum, I use expresspcb.com. Easy to use, easy to modify & save symbols, easy to layout parts on a board to visualize the fit or to capture what you've done. Not the best for actually routing a board, poor rubber banding.
For schematic capture & board design, where I will in the end create gerber files for buying boards, I use eagle from cadsoftusa.com.
Fritzing can make a pretty picture of your layout, but crappy schematics for debugging and understanding what the circtuit actually does, which is what engineers want. I've never seen a decent schematic posted what was generated in fritzing.