for me it does not have to be simulation, just to sit and tinker around with the best layout, i always use breadboard to make things (it's just easier) and of course i have not seen a program that can "plot" components in so you can make a compact layout.

Also i like gEDA - Schematic editor it would be nice to have on the move.

What i really want is to make my own program that outputs this:


This is 75% of my home amp i posted in the DIY audio thread.
As you can see the holes represent the holes in a normal breadboard.