Ok, its the end of the year and my lady has finally let me lose to go wild and get a great set up. Since theres a ton of sales going on right now I feel its the best time to grab some speakers ect but I have a few questions. The speakers I plan to get are as follows:

Infinity Primus P252BK - front speakers 2x
Infinity Primus PC350BK - center speaker 1x
Infinity Primus P152BK - book shelf speaker 2x
Infinity PS210 10 - sub x1
Infinity PS28 8 - sub x1
Onkyo TX-SR806B - receiver

So thats the set up i'm eyeing right now and i've had the chance to listen to infinity sets before and i've always been highly impressed with them. So heres my few questions. oh and i'm just wanting a 5.1 set up. I cant fit a 7.1 properly in my house but 5.1 would work great.

1) For rear speakers would "book shelf speakers" work for that?
2)Yes i'm sure you noticed the multiple subs, i want the big one in front, two others to get for one rear speaker (1 sub each) and the last final sub to fit snugly behind the sofa. I want to feel the action. So how the hell can i hook so many up to a reciever?
3) THX, is something I want. The Onkyo receiver has THX, but the speakers arnt THX certified but from what i hear alot that there are several speakers that can perform THX quality its just the developers dont go through the process to get the speakers THX certifed since it cost more. So would the Infinity speakers perform THX quality easily?

Well thanks for all your time and help, also if you got any idea's please let me hear it.

#edit.
ok after a bit debate I have now changed my subs to just down to 2 now. Orginally I was after 4 but has now been cut down just to two.

Welcome to the forums. You have some very good questions, I will try to answer them.

1) Yes, bookshelf speakers work great as surrounds. In fact, the ideal setup for 5.1 would be 5 identical speakers all around whether they are floorstanders, bookshelves, etc. But, for most of us, we have to compromise either due to budget, space, logistics, etc. The reason most speaker mfg.s make a center speaker is because most people can't utilize a veritcal center.

2) What is the size of your space? You may only need one good sub. Incorporating multiple subs in a room is not as easy as it may appear. If your room is not that big, you may want to get a very good 12" or 15" sub from one of the ID (Internet Direct) manufacturers; Hsu, SVS, eD, Axiom, among others. Infinity makes very good speakers, but there are better subs. Browse the subwoofer forum for more info.

If you really want to feel the movie another option, that might keep your lady happy, would be bass transducers or shakers. These are devices that mount under your sofa that transmits the bass signal into your seat! Look at the subwoofer/transducer forum for more info. This might be a better option for your lady because they are hidden!

3) THX. If you do a little more research, you will find that THX is just a standard of certification that means that, that particular piece of equipment will at least meet minimum requirements. Once you've become educated and understand what you're looking for, you will find you don't need the THX certification. That being said, there are many, many speakers that exceed THX requirements. The reason they don't apply for the certification is because they just don't need to. Quality products will easily exceed THX standards, so don't limit yourself to just THX products.

Just my opinions.

Hey thank you! Your reply was great and gives me a lot to think about. I will take a look in to this bass transducers and take a look at different subs. Yeah every day when I have the time I keep reading more and more about this stuff. I finally checked out all the THX info and how the process is set up ect.

The size of the room is roughly 15 by 18. So yes its not the biggest. Multiple subs may of been a bit over board at first. (hey, one can dream) But you've got me interested in this bass transducers. I'm gonna do some research on it. Thank you for bringing this to my attention!