In the original AC, I loved the sports fair and aerobics days.
In WW, I absolutely adored Bright Nights and Flower Fest, but my favorite was the Fireworks Show.
I didn't play CF very much, but I loved Christmastime.
In NL, I love April Fool's Day, the Fireworks Festival, and Christmas.
I didn't really like any of the events in ACWW, mainly because they didn't really correspond to real life holidays... But in ACNL, I thought April Fools was pretty fun, and Bunny Day was great too (I had great fun hunting for eggs until I got the whole Egg Series and a gazillion pictures of Zipper...). And Toy Day is really cool too, I like how it builds up from when December starts.
I thought the concept of Festivale was cool, but Pave really annoyed me once I got going. And looking for those feathers... Gah.
Only started ACNL in November, so looking forward to experiencing the Bug Off and Fireworks Shows!
festivale was really fun but i think easter was my favourite, even though the furniture is ugly as hell it was really fun going around finding all the eggs!