I'm having trouble participating in this because I've already spent more than I'm comfortable with (on G10 mag-handled FFFBMs). I still sometimes think that I should have bought a Busse AK-47 (are swords and knives the same thing), but was that over my limit because I didn't?

For me, I have max that I'm comfortable spending; exceeding it results in a period of self-recrimination and mild depression over my perceived lack of self-control, but that doesn't mean I never do it. However, I'm not sure that there's an absolute maximum that I'd never exceed, especially if a blade is unique and/or has historical significance -- some bragging-rights fall into the "priceless" category.