I consider myself a role player. I don't think the system matters if the story is focus-based. I tend to prefer Wold of Darkness (the original, with Vampire the Masquerade and Werewolf the Apocalypse, not the new setting) for a basis for modern age stuff even if we're not playing Supernaturals: The Overwhelming Majority" and 2nd or 3rd Edition AD&D as the basis for fantasy. I would also use the Eve-Online setting with a White Wolf-like d10 system for science fiction (if I felt so inclined).
Honestly, the BEST Live Action Role Playing game I was in allowed everyone in a so-called "Vampire" LARP-- we even had Highlander-like Immortals running around. It didn't matter; at one point we went about 6 months without a single power being used because it was all player-driven politicking and plot. In fact, the ST was incredibly cool about us ignoring everything going on around us plot-wise-- less work for him with a 100-person game and one helper. Once the Mages got demolished by the HIT Mks for throwing fireballs at whoever knocked at the door (true story) and the new Prince Bloodhunted most of the surviving Immortals for beheading a few Kindred "just in case they could Quicken them" most of what got tossed around were Social and Status challenges for about a year until we figured out how to manipulate the Storyteller's big bad guys against other players.
In fact, every good game that I've been in has pretty much been a homebrew game, except for Paranoia. Every "campaign" that I've seen that lasted for any length of time pretty much implemented all story-based experience, regardless of the system. How else do you play a politics-based AD&D campaign for years?
I don't believe in "ignoring the rules" on a piecemeal basis; there needs to be consistency from session to session. When I play AD&D, the Wizards have a certain number of spells available and the Paladin must be Lawful Good. There must be balance, as well, so the Wizard is more focused away from duplicating every other class out there, and the other classes are buffed up a bit to be balanced at the higher levels. Every game must have consistent rules internally or it's no longer a game. However, every game I've been in has been about the story and the interactions and choices and politics. Sometimes the choices are about which set of monsters to kill or which Elder to hunt down and drain, other times they are about whether to take the opportunity to betray everyone else for personal gain. Sometimes there seems to be no good choice, and it is up to players (including myself) to find a way to work through a bad situation and still come out ahead in the long run.
One of the reasons I prefer deviating from "known" rules is that it preserves some of the wonder. If you don't know exactly how Diablerie is going to affect you but you know that it will (because you've seen problems with every other person who has done it) then you get really nervous-- just like you should. You KNOW you'll benefit this way and that, but you can't predict the drawbacks even though you know that somehow they are consistent.
As well, one knows how magic works for the Wizard in AD&D, but that person from another land seems to have an awfully screwy-- but clearly similarly limited-- way of handling it herself. In the meantime, no one can get their minds around how to stop that Abomination from wrecking the world if it should ever wake up because how it uses magic is even more alien. And somehow they all exist in the same milieu.
So for me, role-playing actually works back into roll-playing because it can require entire new mechanics and new philosophies (perhaps imported from other games) behind how effects can be created-- and they have to be reconciled theoretically with what is already present and known even if the players never find out how it all works beneath it all. I guess I've been blessed over the years with having a handful of others willing to put the time and energy into creating these sorts of stories and frameworks in which to tell them.