If you want a special paid event, on top of the celebrations at the Parks, many resorts have exclusive ticketed parties (theyre usually very pricy, so it depends on your budget). One that looks great this year is the Masquerade party at the rooftop restaurant of what will be the newly-opened Riviera Resort. I also know many Disney springs restaurants have their own event, I think the Edison last year had a big NYE party as well.