well the caribbean is already an option for me as i have a jamaican passport as well. ghana is also an option in africa as a legal resident, citizenship i'l have to some more research. i just want the flexibility of a third passport.If you had to leave the US I would not do either the UK or EU. UK is trying to keep up/beat the US in implementing a police surveillance state. Combined with austerity and the slow death of the NHS, I don't think you would be better off.
The EU is tacking hard right due to economic and immigration issues. The liberal welcoming Paris for Blacks of the 1960s is pretty much going away I think. Granted it won't be the same as US right wing bullshyt but it will still be right wing and especially antagonistic towards new immigrants.
Asia doesn't really welcome immigrants or give them citizenship unless you have deep pockets and can move to Singapore etc. Australia and NZ may be better but I doubt they would tolerate too many of us. Individually you can go where you want but in bulk probably only Latin America, Caribbean, and Africa would absorb a large numbers of AAs.