If we weren't meant to eat meat, then why does it taste so good? Our bodies have a very simple mechanism to discriminate between things that are good for it, and things that are bad for it: taste. Sure, the mechanism is easily fallible (think: Midori), but in general, it's pretty damn good.
Having known quite a few vegetarians and vegans, often their concern is whether they're getting enough iron in their diet. Shockily enough, they're all female. Most of them take iron supplements (in the form of tablets). Which is more natural? Eating a steak, or consuming a tablet?
If I've learned anything from them (and from 'normal' females too), it's that women need to consume iron -- and in larger quantities than men do. What better source of iron than a juicy steak?
This whole vegetarian/vegan movement has only really arisen in the last 50-or-so years. Humans have been eating meat for millions of years.
I'll finish on that note with a short video clip:
evolution.mpg
Of course, the vegetarians and the vegans come out in their numbers, expressing how offended they are at the clip. Go eat a steak! Live a little!