A big mistake with a little help by your dealer is to give too much money for the amplifier.
The loudspeaker is the critical element in particular today where you find out too much cinema speakers.
So you have to pay much attention at the speaker you buy.
Another big mistake is to look for technology aspect:many marks give you strong information speaking about new technology they use and this fact is only to justify high level price not important for you and get a fine system at a correct price.
Avoid loudspeakers that needs strong amplification to give fine results.
As I told in other post, test the speakers you have to consider with a low cost hybrid amplifier (I mean not more than 800 euro) and if the shop hasn't it change the pusher.
Ok start to hear the loudspeaker they propose you as they best arranged with their best amplifier and cd player but then ask to connect a low cost 50w hybrid amplifier.
Pay attention at the quality sound you get also in this situation and you'll do the right choice.
So you'll never throw out money in the wrong direction.
Only in a second Time you should consider to improve the quality of the amplifier at higher level and after months of experience.
In this way you get a fine loudspeakers that will come with you at higher quality level.
In different way you give too much money for the amplifier and buying conseguently a poor loudspeaker and final cost will be twice changing loudspeaker in the second time and related at the amplifier you bought before...not to do.
You have to buy before the best speaker you can for your budget minimizing the cost of the amplifier able to manage it and you'll get the higher result for your money.
This is particularly true for expensive loudspeakers costing 5000 euro or more.