For me, my personal favorite is the 02-05 3rd Gen trucks, as far as looks goes. They look beefy as hell, and with the 20" wheels wearing 275/65s, it strikes the perfect combination of wheel/tire/wheelwell size.
If I were to lower a Ram, the only choice for me is the 2nd Gen trucks. They look squatter in overall height, and lowering brings out that perfectly, in my personal opinion.
If I wanted a dually truck, I would get a Megacab model, and get the frame stretched to fit a full length 8' bed on her. I've seen the dually Megas... and all I can think is "WTFF?!?" Seriously, it looks like an extremely cheap chinese made oversized fender flare ordered off that really sketchy shop on Ebay. If stretching the frame is out, then I will choose a regular Quadcab Dually over a Megacab Dually.
The only thing I would want a 1st gen Ram would be for making it into a Lil' Red Express copy lol
If going on stocl looks alone... 3 (early), 3 (late), 2, 1, 4