mine is: MXR M82 Bass Envelope Filter + Z.VEX Box of Rock (clone!) with this combination (+ some clean blending via X-Blender) i get very very close to that RHCP "Sir Pyscho Sexy" sound.
MuTron III+ and TAFM, actually running the filter before the fuzz, sounds killer. The other good one is QTron+ with a SPII in it's effects loop.
Still working on a fuzz I like (just traded for a Russian Spy and waiting till I can afford a B3K). I'm currently running a Green Rhino into a WMD Superfatman. My back up filter is a 3 Leaf GR(v1). I like the Fatman so much, I may put my GR up on the block.
My fave dirt>filter combos are thus: TFR or Oxide into Xero D (w/express pedal) and TFR or Rusty box into Proton. I've also been known to throw an OC2 in front of all of the above for synthy goodness. Edit: I've got a FEA Dual Band Distortion coming (I used to have a v1) and I'm sure I'll be using that in combo with both the Xero D an the Proton. I guess I'm a sucker for dirt and filters.
BassBalls into either Brassmaster clone or HM Lo|Fat into a 3 knob BassBalls. I can get it coming or going.
+1 on the Oxide into either the Proton or Xero Deluxe...that there is amazing. I'm also liking: Copilot Orbit > Xero Deluxe WMD Geiger Counter > Proton Oxide > Unpleasant Surprise > Xero Deluxe Unpleasant Surprise > Multiwave Bass Distortion Pro > Modfactor's QWah
If I were to just pick one pedal what do you think I should get? I don't really use filter sounds much but it would be nice to have a straightforward one to have on hand if I want it. Thanks.
Of the two I use, for straight forward, I'd recommend the Proton – its more straight forward than a Xero D. (But the Xero D does a LOT more.)
I used to be all about having my Q Tron + running into my MXR Bass Blowtorch (with BBE Maximizer at the end). However I've been doing some adjustment to my amp EQ and I can't seem to find the funky-screamy-but-still-heavy sound I had before. I just ordered an Enigma Q balls, we will see how that plays out when combined with the blowtorch, I can't wait!