Last year was great for me, so in the olde category, my favorite concerts were:
1) AC/DC - Black Ice Tour, Bucharest they really made a great show, plus it was my first time seeing them
2) Sonisphere Bucharest, the Big four, particularly like Megadeth
3) Alice Cooper at Wacken Open Air. Also a showy type of concert
4) Ozzy, really like gus G at the guitar
5) Overkill, also at Wacken
6) Death Angel at Metalfest, Budapest, Hungary. Never really been a Death Angel fan, but they were really awesome live, I was impressed.
Honorable mentions go to Motley crue, Manowar, Accept, Anvil, Grave Digger.