I agree with what has been said- To add something to these answers I would also recommend for you to anticipate what kind of riding you will be doing the most and thus knowing what extras you might need or want. Crud guards?, lights, panniers, ?... etc Bicyles that have this included in the sales prices could be a good choice, but if you do not need those extras, then no need to spend the money or time looking for them. But most important, since up-grading is always a possibility, make sure this future attachments will fit your bike and that the frame, and the rest of the components will allow you to include these in the future.
Seems to be a trivial matter, but solving or anticipating this will get you a better bike for the money.
Also, ask around and get good tyres for the kind of riding you are mostly interested in (forget big mountain bike tyres, or very city oriented ones). Cantilever brakes would be my option too. And, if possible, 3 chain rings in front, for easier and a wider arrange of gears to have at hand. (hard to change from 2 to a 3 chain ring bike, so once again, anticipate).
Enjoy!!