...After thinking about it, I went and did a web search and within a few seconds, I found an article on an established, trusted website, talking about this very issue. It was a 2 page article; both pages are not very long, so it doesn't take but a moment to read. First, lets just skip page one for now and head right into the Pros & Cons on page 2: http://dinosaurs.about.com/od/dinosaurcontroversies/i/warmblooded_2.htm
I didn't even realize it was debatable, like I said earlier, until just a few days ago. Personally, I'm in between the two conflicting theories of warm-blooded versus the cold-blooded claims, and I think that there were both types of creatures back then. I have to agree with the prior statement, though, and that being it would be difficult trying to imagine a T. Rex, for example, being anything but warm-blooded. I think many scientists just want to believe they were cold-blooded because it is easier to accept - since dinosaurs are known and often labeled as "giant lizards."
It is very possible that we will never know the actual answer to any of this, and due to the outlandish differences in the creatures of the past from the ones of today, who is to say that they couldn't have somehow been designed or born with a unique metabolism that is unknown to us - featuring facets of both warm- and cold-blooded traits. Maybe they had the ability to turn on a self-induced, cold-blooded, internal hibernating switch when slowing down the metabolism was necessary for survival, and then have the ability to awaken to a hyper-active, high-calorie burning, warm-blooded eating machine when possible - who knows?
---End of Post "Were the Dinosaurs Cold-Blooded or Warm-Blooded?"