I use a 28 point buy in my campaign, which I've found to be more than adequate. I play a specialist wizard in a campaign using a 31 point buy (why 31? Not too sure, really...), and have found the party is really quite powerful. 25 points is for the campaign where the PCs are experts at what they do, but are not 1-in-1,000,000 individuals. Remember that the whole xp, CR and EL system is geared towards characters using 25 point buy. I acknowledged from long history that I was a DM with a tendency to create "difficult" challenges for my players, and so went with the 28 point buy.
32 points is really for "heroic" fantasy, where the PCs are so far above the norm that they are truly heroes.
Cheers, Al'Kelhar