I don't know if anyone has mentioned this yet but it's worth remembering that you don't have to concentrate on the MIDI start times to make a part sound less rigid. Sometimes humanizing the durations is what you want, especially if you're going for a very tight groove (electric styles etc). For instance you might have a MIDI bass part that you want to be absolutely rock solid in the timing but it's just a little too robotic. Drawing in some slight variation in the durations will sometimes add just the right amount of human feel. Of course the best way to do this would be to play the part live, quantize the start times 100% (or a little less if desired), while leaving the durations unquantized. In other words, quantizing a live part 100% won't necessarily sound too robotic as long as the durations are left alone. 

sharke
I don't know if anyone has mentioned this yet but it's worth remembering that you don't have to concentrate on the MIDI start times to make a part sound less rigid. Sometimes humanizing the durations is what you want, especially if you're going for a very tight groove (electric styles etc). For instance you might have a MIDI bass part that you want to be absolutely rock solid in the timing but it's just a little too robotic. Drawing in some slight variation in the durations will sometimes add just the right amount of human feel. Of course the best way to do this would be to play the part live, quantize the start times 100% (or a little less if desired), while leaving the durations unquantized. In other words, quantizing a live part 100% won't necessarily sound too robotic as long as the durations are left alone. 

Makes sense, thanks Sharke!