Hello Sean,
To me, what's important is understanding that going with a two handed rod is a specific style of fishing. The whole system was developed for swinging flies and covering water. For example, a person I know got into the two handed game, but has since gone back to his single hand rod as he prefers to stand in one spot, toss a nymph rig and then move on to the next spot. Myself, I really enjoy the cast, swing, step down style of fishing so don't use a single hand rod much anymore. You can fish all types of flies and multi fly rigs with a two hander, and it all works, but it's basically all swinging. As for gear, I use a 12' 5wt and find it's a good happy medium. Cheers.