I love my home theatre but obviously being a home theatre in a box from Best Buy, it's not the best in the world.

It's an AIWA brand AV-D58 DD5.1 / DTS receiver and AIWA speakers... I've been thinking of just upgrading the speakers but keeping the receiver.

Will just getting "bigger speakers" make the sound better? (assuming they are matched brand and of good quality of course)
Will getting "bigger speakers" allow things to be louder?

Thanks for reading my newb questions and I look forward to reading any suggestions, etc.

First you got to take into account the power capabilities of your receiver. Buying bigger and better speakers without the right power source can damage your new speakers and make them sound awful.

Your Aiwa being a HTIB, should be no more than 60watts peak power. I suggest you start from scatch. Let me know how much you want to spend on your HT and and I can offer a few suggestions.

I'll have to check the power capabilities, but thanks for the help, I appreciate it.
My receiver honestly does everything I want it to do, unless it's not putting out enough power for new speakers that is, that could be a problem, but as far as features go, I like it, and was wanting to be as cheap as possible and just upgrade speakers. In the deals forum there is a link to a nicer Onkyo 6.1 refurb'd for $179 which is tempting, but then I have to buy 6.1 speakers, etc...
I'm very happy with this AIWA, only complaint would possibly be the sub, I'm not sure if it puts out the correct sound. The only problems I had with it were cured when I upgraded the speaker wire to Monster Cable.

Thanks!

If you are not sure your sub is putting out the right frequencies at the right time, go to a local hi-fi shop and audition a system with the same cds you play at home. They will be more than happy to accomodate your requests.

Good Luck.

No, if anything it will make things more of a problem.

Amplifier power is what makes decibels in the form of volume. Larger speakers, in general, need more power. Usually good clean high current power.

Underdriving a speaker is a good way to burn out the tweeter.