It doesnt even really matter. If you speak American english, south african english, or hong kong english, or that god forsaken Canadian "english"... English is english and you'll be understood where ever it is that you go.

Im American, and i'd advise you to learn british english.

1, Because, when you go to britian, people wont think you're a stupid wanker.
2, When you go to American, people will LOVE your accent! And they will ask you if you are from luxemburg!

If you learn american english,

1, no one in america will care
2, no one in the rest of the world will like you.