What sort of experience do you have with bicycle mechanics? Mail order is a viable option if you know how to assemble and maintain the bike, but you still need to make sure the frame fits by riding it, not just checking the mathematical correctness of the frame geometry.

Assuming you want a new bike, I'd buy the bike from an LBS, and buy your accesories mail order if the LBS can't offer you a good deal on them. The LBS will let you test ride the bikes, and provide a heap of guidance as to what sort of bike will suit your needs best. The tune-ups they offer and the after sales service is well worth the small amount of additional money. They may even be have some second hand bikes available to help you get a better bike for the money. If you buy soon, you should be able to get a great price on an '03 model.

eBay is a risky option for a second hand bike. Too often I've heard stories of people paying good money for a bike that has seen far more abusive use than advertised, thus needing significant money spent on it to bring it up to rideable condition.