I really don't know why there is so much hostility towards the .40. It is at least an equal to the 9mm, in everything but price and magazine capacity. There is a vast array of loads, from light and fast to heavy and slow. If the issue is cost, then I don't think that should be the determining factor in what you carry. After all, you should practice with loads that shoot similar to what you will carry, and since that generally means mostly famous maker "generic" ammo (UMC, American Eagle, etc.) then the price differential is not that significant.
If it is a question of launching platform (I love my BHP, therefore I love what is shoots, therefore I love the 9mm), I can understand that, but let's be honest.
If it is a question of availability (I might have to take my pistol to the jungles of South America, therefore I want to be able to find ammunition for it nearly everywhere, therefore 9mm is universally available), then that is reasonable, if it is a true possibility. In the United States, however, it is 9mm that is falling by the wayside in comparison to .40 S&W, like it or not.
Given an equal number of shots, bigger holes are usually better than smaller holes. Given an equal velocity, bigger holes are usually better than smaller holes. Given an equal bullet weight, bigger diameter holes are usually better than smaller diameter holes. The heaviest 9mm loads are just below the mid-range weights of the .40. It seems to me that smaller bullets rely more on terminal performance than larger ones, so in general it would be preferable to go with the largest diameter rounds possible, to minimize the need for some specific bullet action (perfect mushrooming, petals peeling back uniformly, etc.) which may or may not occur.
Cor-Bon makes an assortment of +P loads for the .40 S&W, that, for me, make it more than equal to comparable loads in 9mm in terms of stopping power, by sheer size (diameter), if nothing else.
I like the .40 S&W, but I do not delude myself into thinking that it is the equal of .45 ACP. It is not. Neither is 9mm, for that matter. The .40 S&W is a pretty good self-defense round. The 9mm is a good self-defense round, and quite possibly the "floor" (along with .38 Special), below which rounds might not be ideally suited for self-defense. That is a subject of much debate, and any gun is better than no gun which it hits the fan at the local 7-11.
The almost visceral hatred of the .40 on this board is amusing, to say the least. It is not shared by the law enforcement community or the general public. I will continue to own guns in both calibers, but will continue to carry my .40 into harm's way. I do need another good 9mm or two in my collection, beside my HP. Everyone should own a couple, just because they're fun to shoot!