bxboogie,
That is a really, really big question. But, the question does equal one thing - DO NOT purchase from E-Bay or CL. The reason is you will not know what you are looking at. You'll either get lucky or used. Neither is good compared to making an intelligent choice. So, that leaves us with your LBS. Your LBS should not be a rip-off shop. Google the shop and ask around your area to find out what people think about it. To do otherwise is to go in blind. This is especially true because your not yet "bike savvy". If you decide to go to the shop, I'm assuming you'll be looking for a SS or fixed since you asked the question in this forum. Try to stay big name. Schwinn, Trek, GT, Surly. Fit is absolutely everything. Depending on the shop they might not let you in the parking lot on the bike but NEVER buy a bike from any shop that won't let you mount the bike in a trainer. When it comes to fit don't let anyone tell you that you'll get used to anything because you won't. If the saddle is uncomfortable then you want a swap. Reach to the bar feels off? You want a shorter or longer stem. Bar feels too narrow. Need to change that. Expect to pay something for any swap but also expect a very steep discount on the new part and be polite but make them do all swaps. You want to leave with what you want which is a 100% functioning vehicle. You don't want to go home and do anything except ride. If you buy a fixed make sure a front brake is installed and foot retention is highly desirable. SS you want to think exactly as you think with a geared bike - because that's exactly what it is. You just don't have shifters. EVERYTHING should be comfortable in both cases. Make sure to understand their first time tune-up policy. How long do you have to bring the bike back for a free tune up. They don't have that policy or act like they don't really know then you don't want to buy a bike there.