Ok, here's a small list...

X-Men - they all sucked. Big time. I wish I could erase them all from my mind. #3 was a total and utter pile of garbage though, much worse than the first 2 in every respect.

Matrix 2 and 3 - massive stinkers. Story was complete BS, production totally crap compared to the first. Like comparing a master painting to a cheap litho knock-off.

Superman... Only the first 2 originals were any good. The recent one was complete shite.

Batman - 1989 original was good, second was good but not as good. Rest of that 'series' were some of the worst movies ever made. Batman begins was excellent, better than the 1989 Batman.

Blade - first one was quite good, sequels not as good, but 3 better than 2. Blade, IMO, is one of the best cinematic realisations of a Marvel franchise to date. Hell, any comic.

Police Acedmy 2, if I remember correctly, was extremely funny at the time and I ranked it better than the first. Everything else sucked, and number 6 sucked REAL bad.

Pirates of the Caribean - first better than second, but I still enjoyed #2. Just wish they hadn't ended it on a cliffhanger that makes #3 seem like #2 part 2.

Resident Evil - liked both of them equally.

Spiderman... first two were watchable, but not as good as they should have been. I expected more from that franchise. Haven't seen #3 yet, but expect it to be better than the first two.

Liked the 4 primary Alien movies enough, but #1 and 2 were my strongest. I don't have a big enough problem with #3 to rate it below #4.

Predator - liked both equally.

Toy Story - first was definitely better. But neither as good as a number of other Pixar movies - Mosters Inc. and Finding Nemo for example.

Die Hard - probably all the same for me.

Mad Max - #2 was practically in a different series than the first and I prefer it. I also liked Thunderdome but not as much. There is no Mad Max 4 that I've ever heard of (thought someone mentioned that back a page or two).

Fantastic 4 - the sequel has got to be better than the first movie (even though it hasn't been released yet). There was just not much to the first one.

Bourne series - first one was by far better than #2. But not so much because of the story, but Doug Liman's direction. Paul Greengrass (#2 and upcoming #3) is a tool and should be shot for the near unwatchable camera shake he brought to the sequel.

Lethal Weapon - liked them all, but first 2 were the strongest for me.

I don't consider Kevin Smith's Jersey flicks sequels, but rather independent movies that share the same universe. Loved all of them. First Clerks better than the second though (the one true sequel).

Harry Potter - I prefer #1 to #2 but #3 to #1. Not sure how I put #4 in there, but I liked them all quite a bit. It's one of my favorite movie franchises of all time. Disclaimer: I haven't read the books.

The first two Shrek movies were just OK and I can't really say one was better than the other.

Pink Panther 2006 - not technically a sequel, but not quite a remake either. In any case, it doesn't hold a candle to the originals. Kevin Kline absolutely sucked in it. Steve Martin had some good moments, but it wasn't near his best work by a long shot. Beyonce was terrible and should not have been cast in that part at all. I managed to sit through it but was tempted to turn it off a few times.

Fierce Creatures, some would call a sequel to A Fish Called Wanda, but it just had the same actors. Not as good as the original picture anyway.

Indiana Jones - all good, #1 and #3 the best. Really looking forward to a fourth installment, I hope Sean Conery's health is doing well (haven't heard anything about that guy in ages)

The Ewoks movie was almost better than the three new Star Wars prequels. The original trilogy is the true Star Wars saga and as mentioned, I prefer Empire over the other two by a huge margin. I could forget about Ep1-3 completely - though they weren't as bad as the Matrix or X-Men that I want to purge them from reality.

Jaws - there's no competition with the original. Not from its sequels or any other shark-themed movie to date.

Mission Impossible - #1 and then #3. Number 2 was one of those movies that need to be purged.

Charlie's Angels... Umm, is there even a point to ranking these? They all sucked as bad as Police Academy 6.

Chronicles of Riddick was better than Pitch Black (I enjoyed both though)

I'm looking forward to a few sequels that I hope don't let me down: The new Harry Potter movie, next Narnia, Pirates 3, Hellboy 2, new Indy, new Bourne

and not so much looking forward to, but hope they're decent because I'd like to see them: new Die Hard and Shrek 3

And of course one can also hope for sequels: off the top of my head one would be a new Riddick movie taking off from Chronicles.