Don't worry, I just reentered the world of audio a couple years ago and have made every mistake in the book...in fact, I bought a set of Pyle Pro speakers, perhaps the worst piece of crap ever made and a couple really cheap ipod devices before I realized I needed to learn a few things to spend my money more wisely! I have progressed through Pyle Pro crap (retired) >> SLS Q line speakers (great little speaker) >> Polk M40s (less crap, but now retired) >> Def Tech SM450 (very good) >> EMP e5tis (excellent for my mid sized room). So as you can see, I have a full set of "crap" speakers that I bought for the wrong reason (cheap) and now reside in the bottom of one of my closets! So don't feel bad!
Really, the AV receiver will be whatever you want- if you want something that is network ready, if you want preouts (if you think you might get an external amp at some point), if you want 5.1, 5.2, 7.1 or 7.2. How much power do you feel like you needs (Cb10 have decent sensitivity, so you don't need much. I would recommend decent power (60-75 watts/channel, some sort of room correction software and hdmi, which just about every decent AV receiver has...after that, it is up to you if those extra features are worth the money!