I really like wah -> fuzz or wah -> overdrive, as well as fuzz -> tremolo, and soon (maybe today) fuzz -> leslie sim (listen to the live version, not Woodstock, but with Big Brother and the Holding Company version of "Summertime" with Janis Joplin). Also Uni-Vibe -> Overdrive or fuzz -> Uni-Vibe is pretty sick. Oh and OC-2 -> Fuzz. Or octave fuzz -> fuzz. And also pretty much anything with a nice delay, especially a nice, touch responsive distortionish fuzz like the Voodoo Lab Superfuzz. Instant bass "Brighton Rock Solo".