Is there any reason to buy AM3 motherboards over AM3/AM2+/AM2?

The only thing I see in different is the socket and RAM. AM3 supports DDR3, which seems to be a bit of a waste. The socket pins are also slightly different, but the socket is universal so this should not be a problem.

The price different is considerable, making me wonder if if it really is worth it to get a AM3 board.

I hear there will be new 6 core AMD CPUs coming out in Q2, but it`s likely they will be too expensive for me. However, I am also wondering if these new CPUs will be compatible with AM3/AM2+/AM2. This will allow me to upgrade a few years down the road.

So basically, I am wondering if I should get AM3 vs AM3/AM2+/AM2 for:

Price
Future-Proof
Performance