My wedding day is probably the current all time best day of my life. We got a marriage license on Wednesday, and went into the court on Friday. No one knew, and for 1 beautiful day we knew nothing but each other. We had a lot of laughs, and I'll never forget the look on his face when they told us they publish the licenses in the local papers at the jewelers (got our rings AFTER we got married).
Some other fun moments were when I met my husband in person for the first time (we met online in a text based RPG before UO existed). He wore all black to scare the beejees out of me, and waited till I came out to stand up. He has always loved pulling pranks on me.
Graduation day in HS when I sat between my cousin and a good friend who loved to bicker.
The day I moved into my own place after spending six months in between my husband and my parents.
Getting my first real job for an office, and the promotions I've had since then. The day they put a real programming suite on my machine, and met my friend Helena.
Oh, and of course, the day my new PC arrived
But yeah, I'd have to put my wedding day up there. I was scared, happy, and shy all at the same time. It's funny because I wasn't really ready to get married when I did (heck I really had no idae what I was getting myself into), but I'm glad I did now.