I have two different Dist/OD pedals. I'm cheap and a rookie so I didn't want to dump a bunch of money into these things yet. The first one I got was a Danelectro Fab Tone, and the second was a Digitech Bad Monkey.
The Fab Tone was about $20. It basically was distortion with eq (bass and treble) and level controls. I didn't really care for it too much because it was mostly a lot of distortion and even though it had a fuzz level control, it didn't seem like there was much range of effect.
The Bad Monkey Tube Overdrive I got on sale for $30 from
Musiciansfriend. I really like this pedal because the distortion/overdrive effect is very controllable. I like the sound I get with it. It really doesn't have a hard distortion effect. I guess that's why you have your heavy metal type pedals.
I guess a lot depends on what kind of sound you are trying to get. The variety of OD/Dist pedals out there is overwhelming. Even one manufacturer will have several different models. And the sound sample files seem to be colored by whatever amp is being recorded. Definitely confusing.