And good plastics are plastic in the traditional sense of the word: if you drop them, they'll absorb the force by deforming and then spring back into place. Metals deform permanently. In a car that's an advantage, you can just hammer it back into place. With a precision instrument a bent tool is just as bad as a broken one.
I don't know how a Rebel compares against a Nikon in a drop test -- I've dropped my Rebel without issues, but no major drops, luckily. But I can compare the pre-unibody MacBook Pros with Thinkpads from the same era. In the store, the original MacBook Pros felt and looked a lot more solid, but they were really crappy cases. OTOH, the ThinkPad's were tanks. Their plastic cases had a magnesium frame, giving them the best of both worlds. Of course, once Apple switched to unibody and ThinkPad's have started to compromise to compete on thickness the story hasn't been so clear.
I never dropped my camera though, but i do run into things a lot, doors, doorposts, fences and most of all tiny people.
Though with a bit typical lens 70-200 or some people often bring, i doubt the difference in weight of the body plastic vs metal is really noticeable. (plastic rebel XTi 556 grams vs 668 grams metal nikon d80)
Huh?
Typical i have a shoulder or wrist strap, ads (no im not affiliated) peakdesigns' or blackrapids' straps and wrist bands
If any reading this still use the neckband with their cams, checkout black rapids systems or peak designs. It's so much more comfortable then 2+ kg dangling from your neck.
Lighter camera ~ more vibrations.
That's not what I was taught plastic meant. I was taught both plastic and elastic materials deform under force, but the elastic ones (not the plastic ones) return to their original form once the force is gone …
I do prefer ABS-PC or ASA for a lot of my more-adverse condition cases. They're much more heat resilient, and chemical/UV resistant in ASA's case.
Typical metals will have an elastic zone, where they act like springs, and a plastic zone, where they don't, and then they fracture. Brittle materials have a relatively small plastic zone, ductile materials will have a large one.