After some quotes and more research, I am moving away from Dealer-only solutions like C4 and Elan g!. I just don't see the benefits over DIY solutions. I'd rather be able to hire professional help for the installation parts that I am less experienced with (i.e. electrical and wiring), and handle the rest on my own. Therefore, it comes down to Elk or HAI, and HAI OmniPro II suites me best. I'd pair it with the Haiku iPad app, since I'm pretty impressed with the user interface.
Another advantage with HAI is the Windows Media Center integration. I am building an HTPC with Ceton InfiniTV tuner, and it's great that I'll be able to control automation with HAI's WMC module. HVAC looks pretty easy; I just install a few Omnistat 2 thermostats and my AC is automated. The rest seems a bit more complicated:
Lighting
So HAI offers an entire system for UPB based lighting control, and it seems pretty robust. The only thing that turns me off a bit are the unrefined aesthetics of the scene switches. They certainly aren't ugly, but they don't scream "classy" either. Unless someone comes up with any other cons with HAI lighting, it seems like a no-brainer to me. I see bundles and kits on ecommerce sites like automatedoutlet, so this can potentially make buying all the necessary equipment pretty painless.
Security
Not really sure where to start here. Obviously all first floor windows need terminal contacts, some pet-safe motion sensors, and maybe even outdoor cameras as well. The actual installation of this (and all electrical wiring, low voltage, etc) will be done by a professional, so maybe it's time to find a HAI specialist. I'd still like to have the specific component list ready when I consult with the installer.
A/V
As mentioned before, I have a HTPC that will be the source of all recorded tv, videos, movies, etc. The family room will have 7.1 surround, so this is where I need advice. Originally I was thinking that the HTPC inputs into a Denon or Onkyo receiver, and that would feed the tv and speakers. From a media selection standpoint, WMC will allow me to get to the media. But what about controlling the receiver so that the media sounds and looks right? Can HAI do this, and if so how integrated will the experience be? Would I still have to buy HAI HTX?
And finally, whole home audio. In the past few years, my wife and I slowly started to neglect our iTunes libraries in favor of on demand services like grooveshark, and most recently, spotify. The most ideal integration would be if we could control Spotify through the Haiku, but I doubt that is possible. Either way, I need to figure out the most convenient integration of on demand audio with HAI.
For whole home audio, I'm still trying to figure out how all of the components work together. From my understanding, I have two choices with HAI: HIFI 2 or Russound. The requirement here is that I want the ability to independently control the different zones in my home with different audio sources. And at the same time, I would want the ability to play one source across all zones (including speakers used for the family room's 7.1 audio setup). And it all has to be controlled from the iPad, ideally with a unified app like Haiku.
So there's what I know so far. I started this thread with no idea on what I wanted or which type of automation solution best suited my needs. But slowly, I've narrowed it down to a specific brand, and I think with a little more help, I'll know precisely which components will power all the different facets of my soon-to-be-automated home.
Thanks for all the help everyone!