That depends. Once upon a time, I thought the LCD-2F was the clear cut winner over the HD650. However, once I upgraded to a Gumby, it's not such an easy choice. Both shine, but for different reasons. The HD650 has been getting more head time lately.
You're right, they are both wonderful headphones. However, the LCD-2F is a lot heavier than the HD 650. Not a deal breaker for me, but I find it harder to lean back in my chair when earing the LCD-2F.