Favorite game franchise

In no particular order
King's Bounty
Elder Scrolls
Diablo

Gaben

Castlevania
DOOM
Wolfenstein
Crysis
Dead Space

Half-Life for sure.
Max Payne. Second part gives me chills till this day.
Hitman. All of it mostly.
Sonic the hedgehog.

Diablo
Bioshock
Dark Souls
Legend of Zelda
Elder Scrolls
Fable

witcher
fallout
deus ex
dead space

that poll...

View attached image.

I'm not sure if I have one. I tend to lose interest by the third game, no matter what series.

...well, various RPG series are an exception. I lost interest in Final Fantasy after FF10, but Dragon Quest and Persona are still good. And The Witcher, of course.

Max Payne, although i never played 3 :)

Dragon Age
Mass Effect
Metal Gear
Dark Souls
and if portal counts then portal :P

Bioshock

Pokemon

Thief.

Gothic

GTA

Starcraft! I haven't played many game franchises to get a good opinion of most of them, though. Half-Life is nice too.

Half Life
Max Payne
Fallout
Mass Effect
The Elder Scrolls
Wolfenstein
DooM
Grand Theft Auto
BioShock
Metal Gear
Dragon Age
The Witcher
Dead Space
Deus Ex
Batman(Arkham Series)
Hitman
Legacy of Kain
Warhammer 40,000

Fallout
BioShock

Counter Strike

Fallout even tho the most recent one sucked

Quite a hard question, really ;)
But let's say:
Mario
Legend Of Zelda
Heroes of Might And Magic
Rayman
Doom
Magicka
Half Life
Portal
Metroid
Call of Duty (yup, I know, it sucks, but I like it, especially Black Ops)
The Elder Scrolls
Lego Games
Trials
Pokemon
Worms
Sonic (I really liked him in childhood)
Castlevania
Dead Island
PayDay (Does it count?)
And quite a lot more :)

I'm probably going to have to go with Zelda, but that's more due other franchises having a bunch of bad games, or only one sequel. Zelda is consistently great. Also, how is Mass Effect beating Zelda? You guys should be ashamed. !

Dragon Quest still makes me excited about the franchise, Final Fantasy was my favorite during the 8/16 bit era. Actually, I might like Suikoden better than Zelda. Even though it hasn't got quite as many games in the franchise, it's only made a few mistakes and most of the games vary from great to fantastic.

Honorable mentions might be Lufia, System Shock, Arcanum (which needs like four sequels), Master of Orion, Baldur's Gate/Neverwinter Nights, Star Ocean, Tales of * games, Shadowrun (the genesis game was the best game I ever played, and the tone and investigative mechanic for SNES was fantastic), Dark Cloud, Parasite Eve, Wild Arms, Saga Frontier. I like RPGs.

I've not seen anyone mention The Elder Scrolls yet so, yeah, that one :)

Edit, turns out I'm just a sloppy reader but then again, a list of a dozen or so hardly seem appropriate when asking for a favorite...
Edit 2: Turns out I'm also bad at reading in general because listing all franchises you know are a perfectly appropriate answer as well :P

Can I choose The Witcher? I read the books before I'd played the games, so I was already heavily invested in the series when I played the first game a decade or so ago.

Since then they have only improved in every way, and by the end of the third you really feel the characters are old friends.

Mass Effect
Dragon Age
Kingdom Hearts
The Elder Scrolls
Assassins Creed
Bioshock
Final Fantasy (few and far between, I have no problem with X and up plus certain spin offs i.e Crisis Core, Dissidia. The MMO's can suck it and 2-5 are good, 7-9 plus mobile phone versions are in the same boat as the MMO's, I just can't get into them)

I'm sure I have more but those are what come to mind in an instant.
Let's face it you can't just pick one franchise... it's to hard, but if you really force it I'd say Mass Effect.