I am contemplating the move from a SERK to a SESG. I pretty much have myself convinced its not worth the $$$ to make the move. As for the original question, "Thinking about moveing from 2007 Black Ice SERK, which I love, to 2009 or 2010 two tone "regular" Street Glide." that's a whole different story.
First, moving from the old to new frame is probably a step up, however from what I've read here the old frame can be made to handle as well as the new one for a couple thousand bucks. Since I have never received bad advice on this forum I have no reason to dispute that. I went from a 2002 SERK to a "regular" street glide in 2008. It was a a noticablely better handling and riding bike I thought. I think that can be attributed to the cushioned rear pully and additional motor mounting positions of the 2008. Plus, the 2002 had about 35,000 rough miles on it, so it needed some love. The long and the short of this rant is, it's probably not worth what you are giving up for what you're gaining.
With that being said, moving to the non-cvo bike leaves a bunch of cool stuff on the table. Take a good look around your bike and then look at the new one and you will see dozens of attention to detail items that you're walking away from that would cost thousands to make up. Plus, if you look around and do much riding, at least around my neck of the woods; EVERYONE has a Street Glide. You're fairly rare, and relatively unique bike becomes the same thing everyone else has......... BORING!!! (no flame intended to Street Glide owners. They're very sharp or everyone wouldn't have one)
Another thing that most people don't realize is unless you either 1.) leave your street glide relatively stock, or 2.) pay for additional accessory insurance coverage; if you have a wreck all that extra chrome goody on the street glide is just up in smoke. The cvo gets it put right back on, since that's how it came from factory.
The way I see it, once a CVO guy, always a CVO guy. I found this out first hand, my "regular" street glide had to go in short order and I was much happier to be back on a cvo. So, this fool's opinion is........ stick with the CVO.