FWIW:
For wah, you can get the GCB-95 bog standard CryBaby for about £70-80, less if you buy 2nd hand, and these can be modded if you're willing to wield a soldering iron. It's not the greatest tone machine out there, but it sounds reasonably good.
For OD/Distortion, I really like the new Marshall pedals. Built like tanks and incredibly cheap, the sound is not too bad either (IMO). For a really "metal" sound, the JackHammer (JH-1) is pretty damn good, plenty of EQ on the pedal, switchable between OD & Distortion modes. The Guv'nor (GV-2) is OK if you're after a classic OD type tone, again plenty of EQ options. My current fave is the BluesBreaker 2 (BB-2). This has a blues flavoured OD type tone (get away...), but the bit I like is the switchable mode, from the OD to pure clean boost. Great if you're running a valve amp, switch to boost mode, put the volume/level on full, and drive those pre-amp valves! :D I looked into EQ pedals and boost pedals, but they weren't cheap. The BB-2 is about £40-45 new. My personal favourite though is the ProCo Vintage RAT, this gives a really dirty dirty tone, and is pure nastiness in a box. Great fun, but you're probably after something that gives a tighter sound.
Others? I can highly recommend the Danelectro DJ-25 Chromatic Tuner pedal. I got one off eBay from the US for about £20, you can't buy them in the UK for some reason. Plug it into your pedal power supply, and when activated, the screen lights up so you can see it. Another fave of mine is the Electro Harmonix Small Stone phaser. Lush and with a wide sweep, great stuff.
If you're running more than 1 pedal, get a power supply that can run a few at once. I got one that runs 5 9v pedals for about £25. Also, Electro Harmonix do a really useful pedal board gig bag, again, it's around £20-30, but well worth it IMO.
