Don't Toyotas already use AGM batteries, or am I wrong? I don't believe Civic hybrids do.
As an aside, due to the regenerative braking technology—and you may know this as well—the brake rotors generally tend to last longer, as they don't experience the same amount of wear they would in a non-hybrid. I would wonder what your studies I've never seen would show, but then again, brakes are an area where unwise consumers are frequently gouged, and I don't know if they account for that—and of course, you can't tell me, so this is all silly talk at this point.
Regardless, lots of reasons that, at worst, you'll break even cost-wise with a hybrid compared to a conventional vehicle, but there are other potential perks. I personally find them a savings, and this is with taking my buying as many parts on my own into consideration, as I've always done that for all of my cars.
EDIT: Oh, and about leasing:
http://lifehacker.com/5858640/should...or-lease-a-car