I updated the template on my photo blog yesterday. I've pretty much ignored that one for a while, and I was still using an OLD Blogger layout. Anyway, I found a template I like and decided to install it. And that's when I noticed that Blogger now lets you choose to keep your widgets when you upload a new template - instead of having to lose them all, or manually find them in your old template and insert them into the new one. I'm not sure when this started because I haven't changed a template in a while, but this is going to make changing your template so much easier.
Thank you, Blogger, for realizing that after we put all that work into adding our widgets, we don't want to lose them just to change the look of our blogs!