imo lang (also supporting some ideas mentioned)
overrated: (i commend myself for being able to say this)
1) some dunlop wahs, some mxr pedals like disto
2) Nova Delay, sorrryyy i know teh pros recommend this but i really dont get why, it has 8 presets fine, but it can only do so much
3) DS-1, CE-5
underrated:
1) BOSS pedals (i agree with greenweenie) i dont get it! a lot of people complain about tonesuck, and some wisecrack even told me on ym to dispose of my boss pedals (wth, i wont mention his name but pm me if interested) but even mike einziger and dave navarro use boss. Okay pa rin sound ng boss, kahit ano pa sabihin ng ibang tao.
2) DOD pedals
3) DL-4, a lot of people, believe me, bash this pedal, cuz it only has 3 presets, and partly because of nova delay
4)OS-2! regarding its sound, its really versatile imo, so many people wanted this pedal out of their boards asap after buying it
5) metal milf (muff) - great sound
6) Boston peds