These are great! For me:
#5 - Seeing Saturn for the first time in my telescope
#4 - Watching the Europa moon Transit of Jupiter for 2 hours straight
#3 - Watching the overcast sky go dark in 1979 during the mid-morning when I was six...we were watching the solar eclipse on TV at home (they cancelled school) and our location was 97% covered. I looked outside and saw it was like dusk - that's what got me turned on to astronomy. This experience came full circle when I was able to take my children to the 2017 eclipse outside the Grand Tetons in Wyoming this year.
#2 - Hale-Bopp and Hyakutake - so beautiful. I was too poor to own a scope back then so I just enjoyed them with my own two eyes.
#1 - My sister and I were driving from Salt Lake City, Utah to Western Washington in the early 90's. It was past midnight and we were somewhere on a 2 lane state highway in sparsely-populated Eastern Washington. Desert type climate. Hadn't seen a car or lights anywhere for a very long time. We pulled the car over, shut off all the lights, and looked up. I had never seen anything so breathtakingly beautiful. The blanket of stars was so think; I could barely make out constellations.