Ayumi Hamasaki x 3 (2010)
Lady Gaga x 2 (2009, 2010)
Semi Precious Weapons (2010)
Beyoncé (2009)
The Pussycat Dolls (2009)
Jessica Mauboy (2009)
Flo Rida (2009)
I've seen others but they aren't as popular lol
Jessica Mauboy and Flo Rida were touring with Beyoncé, and Semi Precious Weapons with Lady Gaga in 2010

and in 2009 Lady Gaga was touring with The Pussycat Dolls
My favorite ones ever would have to be the 3rd time I saw ayu, since I was super close to the stage!

and Beyoncé's... Beyoncé is seriously born to be on stage!
Going to see Kylie Minogue in the 16th of June!!!