Mitra, I think you're going the wrong way here. Stop worrying about AVRs and their features for now. Do this...
- First decide your final budget which you can (or are willing to) spend on the avr+speakers for now.
- Then decide if you want to get all 5 (or 7) speakers, avr and subwoofer right now based on your current budget Or you want to start with the minimum required stuff (ie 2 front speakers and avr) with your current budget and then add the rest (Center channel, surround speakers, subwoofer) later once you have more funds. Benefits of this approach will be that in the end, you'll get a much better system. Disadvantages will be that it would take a much longer time before you can truly enjoy your DVD/blurays in surround sound. Also, it'll be a costlier option. Both have their benefits and only you can decide which way you want to go.
Once these two decisions are finalised, start looking for speakers. Forum members here will help you figure out which ones in your budget you should check out. No speaker can be auditioned without the avr (or a dedicated amplifier but avoid those unless you are willing to spend even more on the power amps) so you'll be auditioning both. Make sure you note down the avr model used to power the speakers. Post your impressions and details here after the audition. FMs will let you know in case the speakers were paired with the wrong avr. In which case you can either try something else or ask the dealer to demo the speakers with some other avr if possible.
Just reading the specs of avr and speakers won't help you at all. Start auditioning and you'll start undertanding most of the stuff. Only after audition you'll be able to figure out if all these expensive AVRs and speakers are worth it for you.
Just my two cents