like mentioned, getting a bike that fits is the most important thing.

another thing to think about is what level of components you want to get. you're probably thinking "i just want to get a road bike and start riding so any components will do". maybe that is true, but once you spend a good bit of time on your road bike, you'll appreciate higher end components (primarily because of smoother more reliable shifting).

so...at the $1000 range, you can likely find a new entry level bike with lower end components or you can find a higher end used bike with higher end components. if you've got some wrenching skills you could also consider a BikesDirect or Nashbar bike. with this route, you'll get higher end components but a non-name brand frame that is likely exactly the same frame as name brands without the branding.

going with a new bike from a LBS will likely get you some basic fit help, a warranty of some sort, and possibly free adjustments for a period of time...maybe even some discounts on gear and stuff.

think through what you want out of this bike and how to best use your budget and then you'll know a little more about where to target your bike shopping. it can't be stated enough though...fit is the most important thing.