+1 -- I'm no professional, but building an entire system on breadboard hasn't crossed my mind for a long time now. As I see it, there's still a finite chance of making errors on first pass of the PCB (no matter how polished your breadboard design is), so it's a fool's errand to go to massive effort prototyping on breadboard. But of course, that depends on your level of confidence (/arrogance?
), and the nature of what you're working on. Side note: the most interesting parts these days are SMD-only, so you don't even really get a choice.
If I ever did do breadboard work, it'd be to verify assumptions in certain blocks of the circuit -- hence I'd only be building that one part of the circuit. Unless you're building some strange circuit with a giant feedback path looping around the entire circuit, there's no point in building it up all at once.
I also +1 the suggestion of building subparts of your circuit as smaller PCBs, if you still want to build the whole thing with breadboard parts.