Do you think it's fair to say that dinosaurs like the T Rex are more powerful and devastating than anything on planet earth right now?

I would not bet on a T. rex in a contest with a male African elephant.  The elephant has long tusks.

Some viruses, bacteria and a half-wit named Bubba with a 50 cal rifle and a box of dynamite.

Flesh-eating bacteria are pretty devastating! 

A T-rex versus another animal? 

Hmmm. 

They were supposedly 40 feet long and 12 feet high. 

Thats rather large. 

I wonder what T-rex meat tastes like? 

No, forget the movie versions, nature always has predator/prey relationships. 

Let's exclude humans, then.

We have no evidence that T. Rex were devastating.  They were probably in predator-prey balance with their prey animals, and didn't do any devastation to the landscape.

If you want devastation, have a look at:

o Goats.  These guys cause desertification.

o Rats.  Three species cause all sorts of problems.

o Housecats.  Pigs.  Brown tree snakes.  Fire ants.  Yellow crazy ants.  Argentine ants.

Okay, those guys are our introduced animals. Let's exclude them too.

All I have, then, of wild extant animals, are elephants and beavers, and possibly North American bison.  These guys shaped ecosystems.  Past tense operative here, since hunting has reduced their numbers.

It would be interesting to see a T-Rex fight either a elephant or rhino or hippo.

i dont think so

No. Man has demonstrated his power to destroy and devastate which far surpasses that of any creature who ever inhabited the earth.

No. A human with a RPG could take one out. A human with no environmental ethic could take out the entire ecosystem.

Nah, I would say liberals are much more destructive and devastating