I'd really like to see Lionel, MTH, 3rd Rail, Atlas, Weaver, (any others?) build some more smaller engines. I'm a sucker for a 2-6-2, a 4-6-0, a 2-8-0, particularly in more modern trim. These old "teakettles" which were built in the early part of the century, but many actually continued in service right until the end of steam in the mid 1950's.
Most of us don't have the curves or the space to run 4-8-8-4 Big Boys or other huge articulated engines, but these little engines were used everywhere and are very correct on the curves and clearances of most of out layouts. Every Railroad had some of them, and they can, correctly, be lettered for most of our favorite RR's.
I have 4-8-4's and 4-6-4's which are very nice, but to operate a little 2-8-0 with a "way" freight is the true spirit of railroading in the 20th century. Being an older guy, I have wonderful memories of watching these little workhorses doing their jobs.
Paul Fischer