Maybe I don’t spend enough time shopping for Google (GOOG) Android phones, but I always get a kick out of the Top 20 Mobile Phone lists — measured by ad impressions — that Millennial Media posts each year.

In the 2011 report issued Thursday there weren’t many surprises at the top of the list.

Apple’s (AAPL) iPhone, the No. 1 best seller in 2010, was No. 1 again in 2011. Research in Motion’s (RIMM) BlackBerry Curve was still No. 2, Motorola’s (MMI) Droid was still No. 3, etc.

The only newcomer among the top 5 was the LG Optimus 5, which came from nowhere to take the No. 4 spot.

It’s in the rest of 2010’s list that things get interesting. Apparently there is so much churn in the Android market that more than half of the phones in 2010’s Top 20 fell completely off the list in 2011.

You can almost hear the marketing departments’ desperation in the names they chose for those devices destined to be quickly forgotten: Passion, Storm, Vibrant, Cliq, Clutch, Hero, Incredible, Smooth, Dream.

The Samsung Moment, indeed.

The Xs in the 2010 Top 20 list below mark the devices that fell off the 2011 list. For the 2011 list — and the rest of Millennial Media’s Year in Review, click here.