Scott, I don’t think I’d replied to you for some reason, but I think I’m generally in the same boat as you. While I prefer to have one Swiss Army knife-like tool that can do everything, I know that it just isn’t going to happen, or at least it certainly isn’t quite there yet. I use Twitter and Facebook for different things (primarily audience based), so I suppose I shouldn’t expect to have my own site do exactly everything I want it to.
Part of the problem is that I don’t have the skills, the time, or maybe even the patience to make my own site do everything I’d like it to (and if I did maintenance can be a bear), so sometimes picking up pieces of things here and there from other developers or even on other platforms seems to be the result. In some sense that’s why I’m using both Known and WordPress simultaneously (along with a few other side projects which don’t fit into either of those). WordPress does a lot of what I’d like, but the speed, simplicity, and ease-of-use that Known provides just couldn’t be overlooked to give me more of what I wanted. Over time, I do find myself moving more and more under the WordPress banner, but I always hear the siren song of other tools calling, so it may never be under one umbrella.
I also find that using other tools lets me test drive UX, UI, and general functionality to see if it’s something worth building, maintaining, or having myself. And even then, I like to do “manual until it hurts” to raise the bar a bit further.