[feral cat]

does it have to be a series?

Basket case and it sequels are fun
Evil dead series is cool
Phantasm series although B grade horror movies are fun
The House Series 1&2 are better than 3 & 4
Lone wolf and cub (Samuri movies, but very bloody)
I hate hellraiser but some people love those movies
TCM and all the films in theat franchise although the original is superior to the others including the remake by miles!
The Demons series 1&2 being the best of those
The MR Vampire and close encounters of the spooky kind series
Ringu (Japanese original ring) and its sequal and prequals is good although again the first movie is by far the most superior!
Cube and cube 2
The Omen is a classic horror series
Amytiville
The blade franchise
I expect Underworld will become a franchise although it sucks
The blair witch movie ... These suck most of all, but some like them!

etc etc ... prob if theres nothing there you like you dont like horror series and should stick to single movies which are often better anyway!!

Hope that helps