I agree the old west especially the great era of steam would be a good area to go with. The few that Main Street Station put out were nice strikes. The Nevada state seal would also be a great start. I think it's time to get "over the top" creative with the new three hundreds in order to keep them alive.
I'm not an avid $200 collector but I do go for the "unique" ones like Halloween and the Heldorado series. We truly need the best here to keep interest in collecting the three hundreds.
My one and a half cents worth, Jeff Bitzer