I vote for Internal hub gears, on commuters.. now there are many options,
and ranges
latest the 11 speed Alfine, from Shimano.. single speed simple ..
but more gears..

this is also Trek Corp 8 speed
http://www.trekbikes.com/us/en/bikes..._city/waubesa/

You could just have wheels built, of course..

want to haul stuff go more cargo yet Xtracycle long tails do a good job.
add to old bikes or there is the Surly Big Dummy which is a long tail frame..
Trek Corp wants a piece of that market, too.
http://www.trekbikes.com/us/en/bikes...ort/transport/