Frame Dents and Repair - Kinked, Dinged or Bent Top tube, Dent Down tube, etc

is the frame now a write off?
if not, should I try to knock out the dent, fill it, or just ride it as is?

I guess you have to ask yourself is the frame worth the repair? and if you feel particularly attached to the frame then keep it and get it repaired. If you're not then pass it on. Personally I wouldn't ride a damaged frame ;)