A duck call?
Seriously, though. Right now I'm carrying an original Olt D-2 and an Echo poly timber call (cheapie), along with a teal/pintail/wigeon/mallard drake whistle. It's time to pull them out, tune, and start practicing again.
I love the old Hambone calls (Amaden out of Lonoke, AR...but collector's calls now) for soft work. I have an African Blackwood RNT (I liked it better when it was Rich-n-Tone, by the way) that is an open water, screaming, Main Street call, and have used Ditto, Chick Majors, Rich-n-Tone, Thurman McCann, Dan Sprague, and Hohn's Choice calls in the past.
It's about finding the right call for the conditions you hunt and how you like to call. I used to like a call that took a lot of air to push...now I like one that is more subtle. I used to like a lot of volume and hunted a lot more open water. Now I like a little less volume and a little more rasp.