Well... I say Megadeth a bunch of times now (maybe 9) and I love that band, but have bands like Amon Amarth, Metallica, Testament, Motley Crue, etc.. that are awesome to see in stage, obviously the first show from any band that you like (to me) is always great. I don't like Metallica but The Big Four's concert in
Sophia and Warsaw was great!
The best live performance 'till now to me was Megadeth in Buenos Aires 2005, was my first concert ever and is my favorites band.