For me 6 in both incarnations is just a pile of shit and the worst movie of the bunch. Resurrection is utterly stupid, but it is at least entertaining to watch (Busta Rhymes being karate Michael Myers is pretty hysterical). Plus I give them credit for trying something new (for the franchise) with the internet streaming thing. If executed better it would have been pretty amazing.
5 is also near the bottom due to how bland it is. It's almost just a rehash of 4 but now with psychic powers thrown in. Though it does provide two really well executed scenes in the chase in the Myers' house and when Jamie gets Michael to reveal his face. It may be 95% bland, but the 5% that is good is really good.
I cannot however find anything even remotely good with 6. It is one of the few movies I honest to god hate. The plot is stupid, the visuals are annoying with how flashy and strobe like they are, the music is grating, and everything has an echo to it which gets old fast. Even the Producer's Cut is terrible with the plot being the main reason. That and the fact it moves slower than a slug. Yes Halloween is known to be slow, but usually it doesn't make the movie feel longer than it is and tiring to sit through. Simply put, 6 is just utter shit and I really, really, really hate it.
I only saw the first Zombie film and honestly I like it for the direction it took. It isn't great but again, I get entertainment value from it. Never saw 2. I like H20 as well and would rank it as one of the best ones alongside the original, the original second, and 4.