I've heard that coke is actually worse for the heart than meth, despite meth being the more potent stimulant. Something to do with coke's anesthetic properties.
Anyway, the worst meth-health story I've witnessed is a lady who got a horrid lung infection that somehow ended in ovarian gangrene (or something similar) that required an inpatient stay at a hospital, where she vowed to never do the drug again. Needless to say, she went right back to it once on the street again...and she was on her death bed.
Haven't heard of anyone dying from a meth OD, but have read about deaths from longterm injection of "methedrine" in the '60s. And some gnarly psychotic tales of jumping from buildings on a mix of speed/LSD and other suicide stories.
Not everyone shows the telltale physical signs of bodily destruction a la "Faces of Meth", but that doesn't mean it's not severely damaging one's insides. Nutrient deficiencies, sleep deprivation, dehydration, stress on the heart and lungs, and countless other problems can arise from smoking meth. Seems a lot of these could be decreased greatly by just swallowing it instead, which is both less addictive and easier on the body (less "rush" and such).