Buying on-line can get you an okay starter bike. For example...I bought a Nashbar road bike. cheap aluminum frame and all carbon fork with full SRAM Force. I rode it a while and found I didn't particularly like the frame for the long distance riding I prefer. Most of those components went into the Soma Double Cross build I did last winter. Here is the point I'm trying to make. If you are just starting out, and need to just get out there and ride, going this route would get you higher level components than you would get from a brick and mortar retailer. Once you know what you like, then buy/build the bike of you dreams either using the components from the cheap bike or sell it to fund the next bike. You can build a good relationship with a LBS without buying a bike there. There are many in my town. I've bought new from two of them, but a different two are the ones I go to most often. Their service department and accessories are where they make the largest margins anyway.