budget & quality

[curse]

Forgive me if this has been asked before which im sure it has, but the search does not recognize "3.1" or "5.1 vs 7.1".

My question is simple. Would it be best to get a nice 3.1 and upgrade later?
How about a great 5.1 with a nice sub but upgrade as i go? or a good 7.1, same thing?

also on the same track, do the extra two speakers on the left and right get used much compared to a 5.1?

As of right now im looking at the energy cherries that are discontinued with a bic pl-200 sub but all of that is up in the air.

thanks in advance

right now looking at $1300