I always used a slow twist full cheeck snaffle but I recently switched to just a slow twist eggbutt snaffle. It works great and my mare likes it a lot better too. You can stay light in her mouth but when she starts to pull in cross country it does the job to get her under control.
I haven't read all of the answers, but I really like 3 ring elevator bits. The ones with the big "snaffle" ring, the one small one on top and two at the bottom. It's easy to adjust, and you can get single or double jointed. If you have nice, soft hands but a horse that ignores your bit you can put it on the lowest ring, if you feel like you need to work on your hands a bit before that much bit you can just use the snaffle part. I've used it on a few horses and I find it works well.
If you are comfortable riding in 2 reins, I definitely recommend a running gag.
I use this on my OTTTB mare cross country as she gets a little excitable and forgets to listen to me. 99% of the time I ride using it like a normal snaffle, but I have a little bit extra control just by engaging the gag rein when I need it.