if you are going to ride boulevards, the rear suspension systems use up a lot of energy....I like the Shimano Rapid Shift (thumb shift) over the twist grip, but that is a personal opinion.....good front suspension like a RockShock can save your butt....my bikes are older and have cantilever brakes ...chrome moly frames flex a little more than aluminum...heavy duty thorn proof tubes ( I use what the local bike shop supplies to the police bike unit)...if you are close to my age (65) you will probably want to ride more upright, and I find that a BMX type handlebar works well if you have a cheaper bike without clamp on handlebar neck ... after spending a fortune on stems and risers over the last 10 or so years...unfortunately my GT was stolen, so I now use a cheaper frankenbike of left over parts.....I use a skate board/roller blade type helmet..