I'd go for Boca v River. Always wanted to go to the la bombonera
If we are only talking football than there is no point in talking about anything other than this Boca Juniors v River Plate. That is the biggest derby without any doubt. Unfortunately River Plate are struggling in the B division this season so Boca fans have to resort to fighting with either Argentinos Juniors or All Boys supporters.
Aftab, I was at the Bombonera 5 years ago, but just for a normal league game. The atmosphere was very good - the fans behind each goal literally are singing from the start to finish of each half and see it as their duty as supporters to do so. There is one song they sing in each half (about half way through) where the fans are bouncing up and down and it looks like a giant tidal wave which really is amazing.
However there was something all a bit surreal about the support in that it all felt choreographed and detached from the action on the pitch, albeit with great passion. For example, Quilmes, the opposition, were awarded a penalty and the Boca fans did not break stride, just carried on with their song. When Boca were awarded a penalty it wa sthe same, no rejoicing, carry on till the end of the song, but go mad when the goal is scored.
I felt that it was as if the supporters' role was to provide noise in the form of a loud and constant soundtrack, but it did not reflect the ebb and flow of the game - no build up of tension at corners, counter attacks, penalties etc, that I associate with the English game. I was at a run of the mill league game, and on the side not behind the goal however (my hotel had told me that if the barras bravas found out I was English it could get tricky). It would have been great to have attended a derby - and support River of course, not the Boca bluenoses.
The ground is a dilapidated shithole by the way, but has an aura about it that new shiny grounds can never achieve.