It depends on what you like most about sims. Seasons is fun if you love the idea of being able to play in the snow and celebrating holidays! Late night is really fun too because it does give you vampires and more places for your sim to go. Supernatural is fun if you love supernatural things. Showtime is fun if you want your sim to have a career in entertainment. World Adventure is fun if you want your sim to go on trips and if you want a little bit more of a game where you have to complete missions to gain stuff. Ambitions is good because it offers more careers and jobs. Generations is fun if you like having a family themed sim. University is fun if you like the idea of having your sims go to college. So it all really depends on what kind of thing you most want to have your sims do or work at. Right now Target is selling all sims games for 20 bucks so you could get two packs for the price one would normally be to expand your game too.
But out of late night and seasons I would go with late night.
