I don't see that "powergaming" or "min/maxing" can't go hand-in-hand with good playing, skillful roleplaying, or having a really good time.
I'm probably a "powergamer" or a "min/maxer", or an "optimizer" or "characterist". When I'm the guy on the playing end of the game (which had been, until recently, very seldom) I like to take enjoyment from ALL aspects of playing the game ... I like the roleplaying. I like making an optimized character. I like interacting with the other people at the table. I like kicking monster kiester. Getting levels, powering up, making a memorable table presence, all of it.
I've played to-the-hilt killing machines (my current bbn1/clr12). I've played oddly weak characters (a dwarf bard, a craftsman specializing in making magical weapons, not the optimal path for a bard).
As far as stats go, I think they're largely unimportant to fun table-time. I can play a really great character who is a fighter with 18Str. I can play a really great character who is a fighter with 8Str. I don't think it makes me a better person than other people that I can make an 8Str fighter fun to be. Nor a worse person than others that I can have fun playing a fighter with 18Str.
In the end, it depends on the campaign. I, and everybody at the table, liked my garrulous old dwarven craftsmen (my bard singing took the form of topical anecdotes ... the inspirational ones usually involved an exceptionally large troute named George). Unfortunately the campaign was Return to the Temple of Elemental Evil and eventually things got so tough that a non-optimized character put the whole group in jeopardy of wipes regularly and the guy playing the tank had to drop out ... so I retired the bard and brought in a totally optimized fighter type that was a killing machine. He too was very fun to play.
I had a rolled character with unbelievably high stats. We rolled at the table and there he was. I think I had, hands down, the best stats at the table. That character was as fun as any other. I enjoyed optimizing him, with his really good stats. The only downside was that he ended up being so good that when the GM started writing encounters specificially to deal with HIM he ended up pulping other PCs. Among our group that became known as "The Rob's Paladin Maneuver". At one point an encounter obviously meant for my character brought another character (Rob's Paladin) from 83hp to -57hp in one round. Unfortunately my guy was a dwarf and it took him until the next round to stump over there on them short little legs and resoundingly trump the rest of the encounter.
So, of them all, the most abusively overpowered character I ever built was rolled. Point buy, at least, gives me the choice of what I want to do ... if the rest of the group is good on power and killing, I can make a fun little goblin rogue (Grimbold the Mighty!) who makes the best of a bum deal (in that case, starting with crappy goblin adjustments) or I can make something to plug a hole ... and both are totally fun, rounded, enjoyable characters for me and everybody at the table.
I don't see where one generation type makes anybody a superior gamer. Or where optimizing makes you a poor gamer. Or not optimizing makes you a poor gamer.
To summarize ...
If you're a crappy gamer, rolling stats will not force you to improve (by making the best of a bad hand, or forcing you to play something different than you usually do).
If you're a good gamer, point buy will not make you a crappy gamer (by engendering you to take up with the devil Minmax, or letting you always play a paladin).
Real Role Players are not "better gamers" than Powergamers ... they don't even have to be different people!
All of the games I run are point buy because it suits my particular tastes (everybody comes to the game with a character ready). It doesn't particularly make me feel like a better or worse person that I do so. I wouldn't walk out on a game where we rolled 3d6 in order, even. I think that would be as fun as anything else.
--fje