I started with iDialer + iContacts + Greenbutton. My initial attempts to install and configure them failed, but the developer was immediately responsive (like w/in an hour) and gave me some direction. I quickly figured out what I was doing wrong and used the combo for about 10 days. It worked extremely well, but not flawlessly. I wanted to try something different, something that didn't have it's own interface, and I also wanted to try voice dialing (which I still haven't done, but soon).
I decided to give MagiCALL a shot. Rather than pay the $25 purchase price, I went through TrialPay (I'm trying out Netflix) and got my registration code w/in 24 hours. With a little futzing around, I got it up and running. It's an awesome app and has been perfect in the week that I've had it. I haven't gotten into some of the more in depth features of MagiCALL, but so far I haven't needed to.
iDialer, et al, is a great combination with awesome developer support. I really hope that people who use these apps make a generous donation to the developer. If I ever go back (in fact, I'm considering using iDialer with MagiCALL), I'd be willing to give $20 or so. Being able to use GV as your primary number as seamlessly as these apps do make it well worth whatever money you invest.
Thanks to the OP for the great links and instructions, by the way. I have to admit I haven't read through the entire thread, but at this point, I don't think I need to. I seem to have everything I need.