I arrive on time, as that's just the polite thing to do and I'm not fashionable enough for fashionably late. I also like hanging out with people before things get crowded and/or loud, though I enjoy that too.
First day at my active duty station in the air force I show up 10 min early and some e5 staff sergeant tells me I'm late and proceeds to tell me if I'm not 15 min early I'm already 5 min late...fun times
If I know most everyone there, especially the host, I show up on time.
If I don't know most of the people going, I show up like 30 min late so the social lubricant can start flowing a bit before they get introduced to their new best friend.
15-20 minutes late. Gives enough time for a few other people to show up, and 8/10 times the hosts will still be frantically running around trying to finish preparing if you show up right on time.
As close to exactly the start time as possible. That's when I was asked to arrive, so that's what I'll do. While I'm with many folks here in wanting to arrive early to avoid being late, parties are the one exception. I think it is more rude to be early to a party than late unless it is at a public venue where I can hang out while waiting without imposing on the host.
I arrive slightly early (5 mins early) because I always make up an excuse to leave early.
My pet peeve is when there's a party agenda (6pm arrival, 7pm food) and if it's 730pm and food still hasnt been served, I can kindly remind the host that I have to leave by 8pm.
When I attended parties in my 20s, this was a extremely common issue. But as I get older and have a significantly more mature group of friends, Im starting to not have to use my "leave early" excuse as frequently.
I'm not fond of parties myself, but when I go to one, I get there on time, wait for the food, then leave with a full stomach. I may wait for leftovers to take home, but it depends. All I care about is the free food.