By far, my best impulse buy was when I got my Military (CF M390). I always though it was just too big - way too big, but after getting it and using it, I am sold on it!
My worst impulse buy was the Spyderco Assist. It just did not feel good in hand to me at all. I returned it the very next day.
My latest impulse buy, was the Spyderco SuperHawk that I just got in the mail today. It feels like more substancial than my PM2 (CTS-20CP), but a little smaller than my Military. I am very impressed it it, and of course will carry it as my main/EDC blade in the short term to see how I like it in actual use.
Wanted: Superhawk - Found!