[quote name='Kirky' post='428538' date='Mar 8 2009, 12:49 PM']I build a BYOC one, which is a clone of the DOD I believe. Sounds great, but needs to be set up carefully for the bass and amp. £44 and a fun project.[/quote]
That would be a clone of the DOD 440, which is completely different to the FX25 that others have been talking about.
The song the OP mentioned isn't actually an envelope filter but an auto wah. It's got a constant sweep controlled by an LFO. If you want a pedal that will do this, plus cover all the rest of your filter needs, with a sample and hold filter too, the Subdecay Prometheus will get you there. It's currently the forerunner in the list of which pedals I will buy as a backup to my Original Mutron. Great pedal.
If you want something that's a little cheaper but can get this sound, and a fairly conventional filter sound, the MXR Bass Auto Q is a lot of fun. Bare in mind it will be nowhere near as versatile as the Subdecay pedal, which is what IMO, justifies the price difference. Try and buy used too, you'll save a lot of money
I hope you find some kind of help in the above section of waffle!!