Your seasons already seem so much more creative than anything I've thought of!
Mostly I just want all the standard holidays (Harvest Fest, Winter Fest, Love Day, whatever "Easter" holiday there is with the bunny and eggs). I'll also add a Halloween if it's not standard, though I'll probably call it Spooky Day to keep with the Sim Theme. :D
The only other Holiday I know I'll add is an Independence Day of some kind in summer. I haven't thought of a sim name for it yet! In America, for anyone who doesn't know, we have Independence Day on the 4th of July. We grill food, go swimming, general summer fun activities. Also, fireworks! Which I will finally use from City Living. :)