Did anyone here ever stop to consider that the best gun for one person might not be the best gun for another? For example, someone who, should they have to use a gun in self-defense, is most likely to be faced with a group of small to average sized attackers at moderate range is probably better served with a different gun than the person who has to worry more about one or two very large attackers at very close range.
Capacity is certainly an attribute of various handguns that should be considered when choosing a self-defense weapon, but it is far from the only consideration and it isn't necessarily the most important consideration either. As to falling back onto borderline cliches about more capacity never being a bad thing, well it isn't until it is. You see, capacity isn't an independent variable which can be changed without affecting the other attributes of the gun. I'm sure we'd all like a gun that gave us the power of a .44 Magnum, the capacity of a full-size 9mm, and the ease of carry of a .25 Auto (not to mention the recoil of a BB gun) but unfortunately no such gun exists. You see, no one gun can be the best for everything so we must decide which attributes are most important and which ones are subject to compromise.
As to the OP's question, the only person who can determine if 8 rounds is enough is you through careful examination of your lifestyle, where you live, and what sorts of things one might reasonably expect to happen in your area. For me, 5 to 6 rounds with a speed strip, speed loader, or both is enough, but I'm not you and our needs aren't necessarily the same.
Smith, and Wesson, and Me. -H. Callahan
Well waddaya know, one buwwet weft! -E. Fudd
All bad precedents begin as justifiable measures. -J. Caesar