take for example:  shreak---5 or 4 movies(did not take the time to count)ice age---4 movies( coming 2012jurassic park ---3 movies (   personaly i did,t like the 3erd movie)jaws --4 movies) i think)home alone---4)  only wached 2 of those....pirates of the caribbean---4 movies)---i saw the diffrence between the second and 4th film) only saw those2) and the seconde film blew the 4th out of the water,in my opinonim sure you can add the rest......some of the movies posted here you mite like....well we can all have opinons   (: 

*lifts hat* Top of day to you, Sir Voxer.I agree with most franchises you listed out (Shrek is going to be 5 very soon, provided you count the Puss in Boots spin off.), not Indiana Jones to be honest since as it goes right now, we might end up with a great movie, should they make a fifth. (1st: Great. 2nd: Lukewarm. 3rd: Great. 4th: Lukewarm to Good (bite me).)Series that I think deserve a place here could be theAlien(s) series. (1st: Great drama, great horror mixed together with a warning of "we may not like what's waiting for us out there". 2nd: "Let's see how the millitary would handle it." 3rd: "Let's watch that again." 4th: "Mix with first? Maybe?")  It seriously derailed after 3rd movie, it went from a (then) unique space horror to a slasher series. I'm looking forward to Prometheus though since it takes part in the same univerese but they supposedly will take a completely new take on the world (pre-quel for one, probably less Xenomorphs acording to some statements).Star Trek. I love this series but they too kind of forgot what they are supposed to be. Up until Generations, they more or less kept to what they've been good at but after that point the whole series (except 10 and the reboot) took on the feel of a glorified TV Special. (reboot doesn't even have anything to do with Star Trek other than setting).The Naked Gun. Seriously. The First, Second and a half-th and 33 and 1thirdth movies were great but the others were so bad apperently that they are harder to get your hands on than the Star Wars Holiday Special! (Obvious Sarcasm)  Ather lenoro' sharanteh! (Ather's light guide us!)"Food for thought!"

Well, in my opinion, it depends on the plot of the movie in question. I guess part 4 would probably be the max for most series, unless they reboot it or change the original actors, however, if the series is planned out properly, like Harry Potter, they can keep going on and making successful movies until part 8.Most series do seem to screw up at around part 3 or 4 (Godfather - 1 & 2 brilliant, 3 could have been great if they'd managed to get Duvall in it, Spiderman screwed up in part 3, PoC seemed to go a bit wrong in part 3 as well, Predator series went adrift with AVP in my opinion and the least keeps on going). I'd say if planned out well, a movie series can keep on going for many parts, but normally, I'd say 2 sequels are usually enough.

Especially Ice Age i think did it for me, no one was waiting for the last few movies... i have the feeling like they make an other movie so that they can put more toys in your happy meal and create new posters and such, it just becomes too commercial.

i've seen puss in boots.
it's over done the spanish influence.
i completely agree with you faruqui but a sellable film is all that matters.
i mean just look at the recent pirates of the caribbean movie.
there are mixed reviews online and many say that its a buisness movement...
johnny depp didn't even want to take part in it, and orlando bloom and kiera knightly aren't involved any more