Well, I had been doing the full-on vegetarian thing for almost a year until just a couple of months ago. It wasn't as hard as I thought it would be - it helped that I live in an apartment with a couple of people who are mostly vegetarian. However, i just realized that I like meat a LOT, and I have other bad habits that aren't any good for me, so now I'm back on the meat wagon. Mmm, sweet flesh!
Oh, and something I discovered when I started eating meat again - if you suddenly eat a lot of meat after close to a year of not eating any at all, your digestive system will react VERY violently for a few days. Ugh.