noob question...

is it as simple as hdmi out of the pc, hdmi in my reciever, hdmi out of the reciever to the tv? - Yup.

Agreed, it should be that simple.

For me, my Onkyo receiver hesitated a bit and caused about a 2 second delay with sound when changing channels, so I decided to go HTPC --> TV (HDMI), then TV--> Rec (optical audio). Problem fixed. I have since sold all my other input devices, so this really makes no diff for the user experience.

yes, that simple to connect. you may have to tweak the resolution or something, but to get a picture, nope. Most newer TVs will be can be detected by Windows 7 or later without any problems.

Short answer: yes

But if you connect your equipment this way, you probably won't be able to work with your HTPC unless the AVR is on and tuned to the HTPC input. Without power to the AVR and the proper input selected, the signal won't travel to the HDTV, so you won't be able to see/manipulate your desktop until you turn the AVR on.

As long as that's ok with you, then the arrangement you've mentioned will work. I personally would prefer to have the option to use an AVR, but not required to do so... but my efforts to use an HDMI Splitter (to the HDTV and the AVR in parallel) have, to-date, been failures.

My Denon 4311 has a "passthrough" setting for HDMI, where that input is passed through, even if the AVR is off.