I have been trading Amex ETFs and nasdaq Bluechips and got into CME E-MINIs recently. I were planing to get into forex to have more flexibility for my living time, until I got the Europe market Idea. You are right. (Switching markets completely would require re-learning a lot of stuff), but doesn't worthe doing it. For me it's difinitly. It does not mean i will be stoping US market, but somdays you have to skip trading nighttime, so next day you get recovered doing forex or Europe market in the morning (when in Dubai) and afternnon (when in Bangkok). well, it all depand what you want from your life based on your status and personality. I am a bachelor and intend to stay for at least 5-10 years from now, and can't imagine trading at night for whole my precious life period.
Btw, this way you are even diversified. If you have losing day in Europe market, you might have wining day in forex or US market, and Viseversa. Even some days you don't mind trading for whole day. You can trade just US market if you can asure that you have everyday wining, but what if you lose 1 day and another day breakeven, with remaing three winning days and two days off in a week. Then you have a total of 2 winning days in a week only. Sounds not so good.
My experience has been that trading DAX would be much better than the US indexes. Look at the charts and you understand why!
Harold Mitchell, Chairman and CEO of Mitchell and Partners, delivered the 2003 Andrew Olle Media Lecture on Friday 24 October. http://www.abc.net.au/sydney/stories/s974184.htm