One hundred and sixty-five votes later, here are the statistics:
The single category with the most votes is, obviously, "Fixed." However, most voters (65%) would like to have ability scores that change in some way or another over time; they just seem to disagree on how that is done.
26.6% of voters want a player-controled means of increasing ability scores, such as feats;
15.8% want them to automatically improve as the character gains levels of experience (like 3.x and Pathfinder); and
23.0% want both: ability scores that automaticaly improve with level, AND the ability to improve ability scores by selecting feats or somesuch.
Regardless of how they change, the majority (64%) wants them to be capped in some way or another. (And if you count "Fixed" as a type of cap, this number increases to 74%.)
So what does that mean? Well:
IF this survey is representative of the attitudes and preferences of gamers everywhere (it's not), and IF the voters are completely objective and free of bias (we aren't), and IF the game developers will use this information to design the new edition (they won't)...
...the new edition of the game will have ability scores that improve over the length of a character's career, but the DM will be able to cap them in some way or another. Which is about what I expected, honestly.