its part of the enjoyment getting a stable system or it used to be for me but now days I hardly ever tinker with it once its running smoothly. I don't seem to get any of these problems you mention?
back down on your OC or up voltage as it may not be 100% stable my the sounds of it.
Same as. When I was a kid all I cared about was speed and performance, nowadays I want reliability No. 1. 24/7. I've even reset everything to stock and lo and behold no performance problems (apart from BF3 crashing to black screen, but we know that's the game).
Obviously most sensible overclocks can be fine, for a time but electromigration, hot carrier injection etc. etc. if you want your hardware to last years and maintain rock solid reliability, I'm edging towards smaller (and no) ocs these days.
Reliability > performance