Google to Acquire Motorola Mobility - Google Investor Relations:

Wow. I’ve really liked my Motorola phones over the years. Great to see that Moto will be Google’s dedicated manufacturer and excited to see any new Nexus phones made by them.

So I’m guessing this also means that Motoblur is as good as dead?

UPDATE: wanted to add after giving it some thought...

I do hope that Google continues to give the flagship/Nexus line to other manufacturers in the spirit of being open (Samsung is manufacturing the next Nexus, HTC developed the first).

As for diversity within android, HTC or Samsung aren't having any problem competing at the high end and I don't think this acquisition will change that. Both HTC and Sansung have made Nexus/flagship devices and I don't think doing so gave them as much of an edge in the market as their making quality devices that people loved (HTC's EVO line, Samsung's Galaxy line).

If anything the acquisition should increase product diversity for android by lowering costs and uncertainty for all current and future (Amazon?) android device manufacturers. Both HTC and Samsung are lauding this move as most of their problems in using android were related to patent litigation and this announcement arguably just took care of that.

A nice side effect of this is that the manufacturer's can put more effort into designing better phones, rather than into litigation defense.

Sure, this announcement will affect market OS diversity in that android is now cheaper to manufacture for but I don't think this move will kill off any OS that wasn't already dead. If the only thing keeping an OS alive was its lawyers' threats of patent litigation, and that threat can be effectively killed by purchasing an IP portfolio, that OS was weak to begin with.