I know this is gonna sound like such a cliché, but I was going to say that RE1 is the most important one as well since it technically started it all... But I didn't want people going "omg duhhh obvious!"

How is RE5 the most important for the series from a story perspective?!

SFII defined the fighter genre, period. Point taken though, but I just meant people giving the nod to original games simply because they started a franchise. VF1 was just the first move to 3D "graphics" in a genre that owes it all to SFII. I can elaborate as to why I think VF2 is more important (much like T3) but I'm off topic already. Also the first true 3D movement in the genre was implemented stealthily in the Kazuya-exclusive sidestep in T2.

In retrospect, if I were to really push it, I'd credit RE2 for breaking the AITD mold. RE1 was being compared heavily to AITD as I remember, and for good reasons. Time has been much kinder to RE1 than it has to the AITD series though. What a sad way to go for that one.

If we were to look at it another way, RE1's success naturally paved the way for a higher budget game with RE2 (which is still the best selling single SKU in Capcom history on the PS1). The franchise came at a prefect time for Capcom, and after all these years, it's still their cash cow globally.

RE5 shown us Spencer's true motives under Umbrella so as Wesker's, unstable world situation - BSAA, Tricell - Global Pharmaceutical Consortium, etc.....
this makes RE5 story most interest and important IMO

However, without the events described in the first game, RE5 might not have happened at all. And it would have changed RE2, RE3, RE: CV etc. If not completely nullifying them.

Precisely what i was thinking. Without the beginning of the story, what's the point in having the end?!

Biohazard is the most important of them all. It started the series, introduced 3 of the central characters, was made even better with the remake and like David said it started a unique sub-genre in gaming.

RE popularized and put a name on the horror genre (right on the JPN box no less), but AITD on the PC is what started it 4 years earlier. To this day, I doubt Mikami's claim that he was only influenced by Sweet Home.

However, the success of RE and then RE2 created a number of me-too titles (ironically 2001 AITD TNN was one of them), and only SH stood out. Years later, Mikami undoubtedly influenced third person shooters with RE4 (the shooting, the dynamic and clever use of QTE's etc).

I think in a way RE4 can be considered more important in the sense that it influenced the industry and other genres on the whole. With that said, it was sort of sad to hear Takeuchi blurt out bs such as "Gears influenced controls" and implement those really odd selective corner cover prompts in RE5. Execution wise, RE never imitated but had imitators.

Re5 may well be the most important (storywise) after re1 simply because it ended the umbrella arc. its doesnt matter if u like it or not. it did ended it.

Who said anything about liking it?