James Bond vs The Land Before time
Which one will end first? Which one will have the most movies? Is there any other movie franchise with more sequels than these two?
If the Land Before time series lasts another ten to fifteen years, I think it will eventually surpass James Bond in number of movies as it's up to 12 movies in about 19 years compared to 21 James Bonds (or 22 depending if you include Never Say Never Again) in about 47 years. However I think it will be much harder for the James Bond series to end compared to The Land Before Time.
As for number of sequels, a few of the slasher flicks such as friday the 13th and Halloween are up there, although I don't think they have surpassed these two.
Also, the national lampoons are a dime a dozen now, but I'm not sure if that qualifies as 'sequels'.
There are a series of british films called 'carry on' which are apparently up to 29 movies although I don't think it centers around the same character or story, so this probably wouldn't qualify as sequels either.