There are a few...
1) It all started with a production of Grease for me (I was very young then) but I discovered the 'world of musicals' because of Grease. I remember how much I enjoyed the show at that time and wanted to see more shows... seeing this production today would be a totally different experience obviously.
2) Definitely Cabaret at Studio 54!!! I remember seeing the show for the very first time and it just blew me away (in EVERY possible way).
3) A strange one but up to now, I think that the opening number of The Lion King is one of the most amazing numbers I have seen. I am not a fan of the show but I remember seeing Circle Of Life for the first time and thinking I was on a different planet. It was amazing.
There are more examples like a few performers that blew me away, closing nights, anniversaries I was lucky enough to attend but the list would be a bit too long, I guess :)
QM
'He really wasn't good as Fieyro. Is it just me or does he sort of come across as a pimp? Just...the hand motions I've seen him do and the attitude..not that Taye is a pimp.' - SallyBrown on Taye Diggs as Fiyero