questions on sound system

[slimy00]

Hi, I have some questions about sound system. First, I have....50'' or 52'' (i don't know model names for almost all electronics) sharp 1080p n some sony blu ray player(again, don't know the model) in a room that's kind of boxed in...its like 15' x 15' room or something, I was wondering if the speakers on the tv n reasonable priced sound system could make a big difference in this situation. And if it does have a big difference n if its worth buying the sound system, what would be a good choice for it?

I also have a 42'' panasonic plasma n ps3 in my room which is about the same size, maybe a little bigger. I would like to ask a same question for this one also.

Sorry for wasting ur time to read this n thank u everyone who would be willing to answer it