Then you shouldnt be buying online, there is no way you can buy a proper-fitting bike from the net, unless you know what size and geometry is right for you.

You need to go to a proper bike shop and see the bikes for real.
You should be able to chose from 3/4 different brands across a few bike shops, but go with the shop you like best.

The real question you should be asking is, how can I find a good local bike shop.

What kind of riding do you want to do
(road/MTB/touring/commuting)?
How big/athletic are you
(ie do you need special fitting or will stock bikes be OK)
Where do you live?
That should give people enough info to help more.