Definately Joints, rolled from pure hemp papers, literally, they are called "Pure Hemp" papers, I buy them online, cheaper than standard papers.
I think keeping the flavor of what I'm smoking is part of the experience, also it's smoother than blunts. I don't smoke cigarettes, so there's no appeal in tobacco leaves for me. Also, a joint can be as big as a blunt if I want it to be, also, conversly, when people roll blunts there's usually only a joints worth in it, the rest is the paper and leaf.
Another reason I prefer joints is the roaches. You can easily open up or even just relight a joint roach, blunt roaches aren't so easy, or tasty, you're likely to have only paper in the ends of a blunt.
Then there's the time it takes to roll either. Joints can be ready in minutes, blunts are a whole process, with less guarentee of success.
Another reason is, Blunts seem like, how do I put this, a novelty thing. As in, people hear the word "blunt" and think "whoa, a blunt" when the reality is, you don't get much higher than with the same amount in joints, people hang onto them longer, they are harsher, and frankly, the tobacco they throw away stinks up my trash can, or carpet.
Did I mention that blunts usually hide the taste? why pay for good tasting pot when I can't taste it? I know they have "flavored blunts" but the same problem exists, and I have yet to find one I consider good tasting. Joint's are plain blank slates for the weed to shine through, some can be stale, but not nearly as bad as an average blunt wrap. And with the Hemp papers I mentioned, I rarely taste anything but the pot.
So, overall, I'd definately prefer joints, but if someone insists on rolling a blunt with theirs, I won't refuse.