What Titan said about balance between different types of games is very important.
I've played games that were nothing but roleplaying, which was... fun. I do get into my characters a ton, but I do like some combat.
Then I've been in games that were nothing BUT combat, and I hated the hell out of them. I build my characters in a way that makes sense with their personality, I don't min-max. Nothing but combat just gets boring, because frankly, hack and slash (imo) is just better in video games. D&D's strong point is the ability to play and interact together in person and be immersed in another world. If all you're doing is fighting and screwing around, it just kills the entire point for me.
So it's important to listen to your group, see what they liked and what they didn't like after each game, and adjust for future games. It's important to keep true to the story you have planned, but it's also important for the players to enjoy it.