[What follows may seem like a rant against the OSR. It isn't. It's my perceptions, which are doubtlessly flawed, and an explanation of why what I perceive about it doesn't work for me personally, given my perception of the history of the hobby. Your own mileage can and doubtlessly will vary. That doesn't make your gaming "badwrongfun" in my eyes. Offer not valid in US Virgin Islands. Go forth, kill things and take their stuff.]
While my dice are old, I don't limit my gaming to any one "school." I think this is largely because much of what the Old School movement seems to espouse doesn't really resonate with my personal gaming history. I got into the hobby in 1978, very much in the heart of that period. My first version of D&D was the Holmes rules, mixed with stuff from the White Box and supplements, and even the first two AD&D books (the PHB had just come out when I started playing; we had to wait almost an entire year for the DMG). During that time, I also played Metamorphosis Alpha, Traveller, Top Secret, and En Guard!. I read Chivalry & Sorcery (or tried to, at any rate), and played the hell out of Melee and Wizard. All of those games are arguably "Old School," but whether due to the OGL making retro-clones of D20 easy, or the preferences of the folks writing OSR materials, "Old School" has become shorthand for "Earlier versions of D&D." And that seems to be a bit of a Whig History, in my opinion.
There was so much going on back then. So much more than just D&D and TSR. Yes, it drove the hobby, but when the hobby was young, there were tons of cool stuff out there. Granted, a lot of it was hit and miss, but the important thing to remember is that D&D was hardly the only game going. Furthermore, the notion that story-driven gaming came about due to White Wolf and the success of Vampire is really pretty far off-base (I've also seen it blamed on DragonLance, which is equally laughable). I've got copies of Alarums & Excursions from the late 70s where people were cheerfully debating the merits of a plotted campaign vs. a sandbox. They didn't use those terms, but it's the same discussion you can find on countless game forums and blogs today.
But I digress. To my mind, thinking just in terms of "Old-School" is a pretty fruitless endeavor. Around 1984 or so, I remember having a conversation with a friend wherein we were looking at the games out at the time and grouping them by "generations."
The first generation consisted of D&D (all editions), and its immediate imitators. If I remember right, our big distinction of a first generation-style game was the use of classes and/or levels. So Tunnels & Trolls was in there, as was Chivalry & Sorcery, Top Secret, Metamorphosis Alpha, Gamma World, et al. Even Villains & Vigilantes, and Palladium's house system fit this criteria.
Second generation games got away from the Class/Level distinction and might incorporate a unified task resolution system. Character generation was still random, though there were often more options to flesh out the character. Traveller, RuneQuest and it's offspring (Call of Cthulhu, BRP), FGU's Aftermath, Bushido, and Daredevils (which all used the same system),and later versions of Boot Hill come to mind (earlier versions of Boot Hill were still in that proto-RPG stage. I consider them sort of a pre-first generation).
The hallmark games of the third generation are Champions/The Hero System, In the Labyrinth, and its offspring, GURPS. These games featured unified task resolution as a matter of course along with structured character creation where your character was built rather than rolled up. The use of points to level the playing field made a mini game out of character creation (and optimization, another thing that is hardly a new development). Champions, in particular, brought about the notion of Disadvantages: intentionally taking on handicaps and personal or social problems to flesh out your character and get more points to work from. Granted, this created more room for abuse and optimization, but it also gave players and GM's tools to use in-game in order to better emulate the genre.
(While story-driven gaming certainly existed before the third generation, for me personally, it became my chosen style of game during the third generation, when Champions took over my imagination and didn't really let go for the next twentymumble years. I maintain it's impossible to run a "sandbox" superhero game and have it look anything like the genre its emulating, because comic book superheroics are an inherently reactive genre. The heroes react to external stimuli. In a sandbox, the world reacts to the heroes, who drive the direction of the campaign. They're polar opposites. Which is not to say a superhero campaign is an exercise in railroading. But that's a conversation for another day.)
According to the conversation I'm recalling, Victory Games' James Bond 007 was the first fourth generation RPG. At the time, I think we based this more or less entirely on the fact that it featured a one-roll task resolution system, where margin of success or failure determined additional outcomes (damage, winnings at the gambling table, etc.) Looking back, I think there were several other features that marked it as such: it was the first really successful licensed game (NOTE: THIS IS WRONG - I FORGOT CALL OF CTHULHU); it was completely devoted to genre-emulation instead of simulation: there were elements clearly at variance with reality that jibed with James Bond's world, and that was how it should be; there were mini-games scattered throughout that utilized the one-roll task resolution system to add suspense to actions that might otherwise be handled by a simple "roll to see if you succeed" approach. Other games in this generation (IMO) include Marvel Super-Heroes, DC Heroes, Conan, Chill, Ghostbusters, and Star Wars.
(By this point, the astute reader might notice that these generations are not precisely chronological. GURPS post-dates a number of fourth generation games by a couple of years. But it's clearly a third generation design, being the bastard lovechild of Champions and In the Labyrinth.)
Arguably, Vampire: the Masquerade is also a fourth generation game. But it kicked things off in another direction, and I'm happy to concede that the Storyteller System marks, if not a huge mechanical shift in RPGs, a massive philosophical one. Pretty much everything that's come out since has been a response to it, either taking the same philosophy further from the previous generations or recoiling in horror and retreating to more comfortable territory. And because I like multiples of five, I'll grant it fifth generation status.
So what does this mean, really? Not a lot. I still love playing Champions. It's certainly changed a great deal from the game I first played in 1982, with loads of rules and improvements. But even with a Sixth edition and pretty hardback books, I still consider it a third generation RPG at heart. And I have no desire to go back and play the 1st edition rules. Seriously, they were an incredible leap forward in the design of RPGs, but to my modern eye, they're diamonds in the rough, still mired in the ground trod by those who came before. (Also, Mechanon didn't have Life Support. That always cracks me up.) If I'm going to play it, I'll take the new rules, thank you kindly. To my mind, that doesn't make me New-School. I still think of Champions as one of the granddaddies of superhero games. It's still Old-School in terms of the core mechanics; it's just been fine-tuned over the years.
So yeah, I play story-driven games with non-random character creation. And I play them sitting at a table with my friends, with paper and dice, and bags full of unhealthy snacks. And it's that last part, if anything, that makes me an Old-School Gamer.