l live in a somewhat urban area with some traffic but l like to ride around the parks a lot.To commute l ride through the streets during rush hour.l like bicycles that are not so bumpy but are not so heavy with wide handlebars.Do you know of bikes that are sort of inbetween a mountain bike and a road bike?

they r called hybrid bikes but l strongly reccomend mountain bikes, they r the suv of bikes,the go anywhere, do anything bike, the only thing limmiting its performance is you,i reccomend Cannondale

http://cannondale.com/bikes/09/cusa/adventure.html
http://cannondale.com/bikes/09/cusa/comfort.html
http://cannondale.com/bikes/09/cusa/comfort.html
http://cannondale.com/bikes/09/cusa/model-8SS1.html
http://cannondale.com/bikes/09/cusa/touring.html
http://cannondale.com/bikes/09/cusa/model-8FSP1.html
http://cannondale.com/bikes/09/cusa/co2.html

It sounds like you'd like the flexability of a moutain bike but without the extra ''bumps'' from the knobby tires. I'd recommend u find a good hardtail mountain bike u like & swap the tires to some more urban treads. Maybe something like the Maxxis High Roller SS or the Holly Roller urban tire. or if u want something a little skinnier & easier to pedal, the Oriflame is a good choice but isnt as grippy.

That set up should give u plenty of stability for hitting up the parks but also be solid for commuting on the streets.

l have a hybrid, and it works very well for the riding you describe. Hybrids take 700c tires, which roll better than 26'' tires. l have knobby tires for winter and semi-slicks for summer. They have straight or riser bars, and position the rider higher than either a mountain bike or a road bike would; so they're good for seeing over cars in traffic.

All the major manufacturers make hybrids.