Which HT receive should I get for my first HT system?

Hi people. I'm contemplating on starting my first ever HT build using an HTPC (which is my current rig comprising an Opteron 185 dual core, 2GB RAM, X1900 XT 512MB (non-HDCP), X-Fi XtremeMusic, etc.) in a 12' x 8' room. The list of receivers I'm looking at include:

1. Cambridge Audio Azur 640R;
2. Rotel RSX-1057;
3. Marantz SR6001;
4. Yamaha RX-V861; or
5. Onkyo TX-SR804.

Basically, I'll run a DVI -> HDMI cable from the X1900 XT to the receiver for video and a Toslink cable from the X-Fi to the receiver for audio. Other than that, I also have a broadband TV box that has component out. The other item that I may possibly add to the HT system at a future date is an Xbox 360 or PS3. In the future, I intend to play HD content via a BD or HD-DVD drive upgrade on the HTPC. I'll be keeping the 37" Toshiba LCD TV that does 1366 x 768 and I think the Opteron 185 should be good enough for 720p when I do the upgrade down the road.

The list of speakers I'm considering are as follows:

1. Paradigm Cinema 110 CT;
2. Klipsch Cinema 8 + Klipsch RW-8 or RPW-10 sub; or
3. Polk Audio RM6900.

Due to space constraints, I'll only be able to use these "budget" bookshelf speakers. Otherwise, I'll have to turn to a floorstanding 2.1 setup and forget about 5.1.

As I understand, receivers 1 and 2 excel in the audio department but lack many video functions such as analog to digital upconversion and video upscaling. On the other hand, receivers 3 to 5 all have analog to digital upconversion and in the Yamaha's case, it also does video upscaling. However, audio coming from the latter three may not be as good as the first 2 receivers. Concerns I currently have are:

1. Although receivers 1 and 2 are supposed have "audiophile' grade sound, am I going to notice this with the bookshelf speakers I've listed above?
2. Should I just get a $500 entry-level receiver with these speakers?
3. Should I be concerned at the use of "pass through" HDMI switch on the Cambridge Audio instead of a "repeater" HDMI switch which is supposed to be better?
4. What is the signifance of video upscaling? Will I notice any improvement in IQ vs non-upscaled SD content on my TV?

Sorry for the long post and it'd be much appreciated if you can provide a n00b with some feedbacks concerning my choice of receiver and the concerns listed above.

Many thanks!

edit: added links.

Thanks for the reply. I'm well aware of the fact that my X1900 XT doesn't support HDCP and I'm prepared to get an HDCP compliant card when I do get around to building the thing. Anyway, I don't plan to jump onto the HD bandwagon until the format war is over so that probably won't happen anytime soon.

Unfortunately, I don't think the dealers at were I live carry the speakers I've listed and they'll have to specifically order them for me and it may be difficult for a listening test.

Yeah, everywhere I go tells me I should try to arrange a listening test before buying the speakers. Anyway, I'm now considering the Mini Monitor v.5 fronts, CC-190 center, ADP-190 surrounds of Paradigm's Monitor v.5 series and a PDR-10 sub. Maybe that's a better long term investment than using those receivers with the wall mounted solutions I proposed earlier.

Getting speakers from the Monitor v.5 series would push the costs over my original budget (I haven't even included the price of the speaker stands and cables in the total cost yet ). Having considered that the room I have is relatively small, I'm hoping that the PDR-10 is sufficient for now.

I note that the Cambridge Audio and Rotel receivers do not appear to have auto setup for the 5.1 speakers. What does a manual setup involve? Should the user's manual include instructions for a manual setup?

Having demoed a whole bunch of speakers, I've finally settled on a setup which does not contain any of the speakers or receivers in my original list. I ended up getting:

Receiver: NAD T753
Fronts: DALI Royal Menuet II
Center: DALI Royal Vocal
Rears: Klipsch ProMedia Ultra 5.1 satellites
Sub: Wharfedale PC8+

Now I'm glad that I had taken the advice of you guys by auditioning a bunch of speakers instead of basing my decision on online reviews. I kinda skimmed a little on the receiver by getting a last generation model with none of the bells and whistles such as HDMI. But the NAD sounded excellent in live tests and I guess that matters the most at the end of the day. I also saved major $$$ in the rears by using second hand PC multimedia speakers (still THX certified though) obtained from eBay. I mainly use the system for music listening in stereo mode and I think the rears are fine for now. With the savings in the receiver and rears, I was able to get the DALI fronts and center which costed beyond what I've originally anticipated for.

I'm very impressed with this setup and I think it sounds a lot better than any of the other receivers/speakers I've had a chance to listen to. Jazz and classical sound crisp and clear on the fronts and voice is great too. The sub also gives me the bass I want in drum & bass (hopefully I won't be getting complaints from my neighbor ) with the fronts maintaining the clarity at high volume. Of course, movies sound so much better than the Yamaha HTiB the new system replaced.

You guys can check out my thread at Rage 3D for pictures of my new setup.