Dan,
I agree with Lee on this one, I'd say the scale Atlantic would be at the top of the list. I am a Legacy guy so I do not own any conventional engines but I do have a Legacy PRR Atlantic (Lindbergh) and love it.
About the same time Lionel did several conventional steam engines, 0-8-0, 2 truck shays, K4 Pacific, 2-6-0s, 2-8-2s etc. When I was looking for a Legacy K4 they would pop up a lot. Look in the 2011/2012 catalogs they all looked nice.
JohnB