I wouldn't worry about separate amps at this time. Get a receiver that has all the features you need and then if you still would like to experiment, you can always save up and add one later. This gives you a chance to evaluate what is most likely all you really need, a good receiver. However, if you decide you really want a separate amp later, you will still need the receiver to be in control anyway so it will not have been a waste.
With great power comes Awesome irresponsibility.