Almost te same. Still, there is a difference. 'Ich würde gern (gerne)' has more air of wishful thinking to it - 'I'd like' - whereas ich möchte sounds closer to reality. Also, 'gerne' itself has an immense role in the sentence, because if you say 'Ich möchte gern eine Bank überfallen', it may still sound more like wishful thinking. If 'gern' is not in the Sentence, it may sound like you really mean it.