I tend to favor targets that are specified for the range that I'm shooting. Of course, if it's shotgun day then who can resist some sort of bottle or can filled with water???
Pistol, it is usually IPSC targets that I print out from the net. 7 to 15 yards, with a silhouette that is on an 8.5" x 11" paper. I don't bullseye shoot with my pistols, they are for defense. All my shooting is training that way. I'll occasionally shoot at paper plates with my .44 revolver, to see how far I could reliably hit deer with.
Rifle, AQTs and Redcoats and 1" squares. Basic Appleseed targets.
I really like the Shoot-NCs because I like instant gratification, but I'll likely move away from those if we're going to get serious about going to more competitions. The bright orange or yellow splashes make it way too easy to see where my shot landed, and I focus more on that than on my sight alignment, which is not good in the grand scheme of things.
For me it all depends on what I am shooting, firearm wise, and what I intend to accomplish. For centerfire rifles at moderate ranges, say from 200-300 yds, I like the shoot-n-see large circle targets. They make it way easier to find my impacts at long range. For handgun work at close or moderate range, I like the B-27 silhouette. For handgun work at longer range, like 50yds or more, I like the single bull rifle sight-in target from Birchwood Casey. Now if I'm going to go out and just plink, then I really like my steel targets ( I got them from metaltargets.com), bowling pins and water bottles.
i tend to shoot at 2 types of paper targets. one is the ipsc metric target (like coach, the one with the upper A/B zone) and the SEB targets. both have their place and the number of different drills you can do with the SEB is amazing.
i also have a couple of plate racks and about a ton of knock over steel targets. when i have the kids out for a range day, the steel is a big hit (pun intended).
Well, the old joke would have me answering "cans"... but that wouldn't be true.
My range has 5-bullseye targets as well as half-size silhouettes, and on occasion, I'll also get one they have with a pic of Osama bin Laden. They also have full-size silhouettes, but I don't use those.
I prefer the 5-bull targets for rapid acquisition, changing targets between shots and also the fact that at their largest point, they're still smaller than the average human chest or head, so if I hit anywhere on them, I'm going to hit the hypothetical BG. I'm not dead-on to the bullseye, but even doubling my usual groups ("half as good as your worst day on the range"), I'll still hit my target.
I normally shoot at police silhouettes, 22" by 35" more or less. I just bought 30 of them at the Rochester gun show for less than $20. When I run out of those I make a smaller version out of paper grocery bags until I can more silhouette targets at another gun show.