I have a question about pedals. Which pedals are the best for metal? Is distortion really needed and is overdrive the same or is it similar? And I have seen in some music dist. is that a pedal or what??

Ibanez Tube Screamer, or Line 6 Uber Metal.
Two of the best pedals out there for a metal sound. I'm not going to elaborate. Hopefully someone else will

I myself, am a very bare-bones, and dry player, when it comes to my effects. More so out of habit, then anything else. I've grown accustomed to never using effects, because I've never been albe to afford them. I once borrowed a buddies rack, some delay, wah wah, some overdrivers (ibanez tube scremaer) and, I just found it more of a novelty, and distraction then anything else. In terms of stompboxes, ive heard great things about Tubescreamers. Man bands do interesting things to clean up the sound of their amps. If you're going to play very low-end foccused, muddy amps (Rectifiers) you could put sometpye of overdrive pedal in the circuit (guitar, pedal, amp) and crank the tone, and volume, and cut off the gain, and fire it up. It'll act like a signal boost, tighten up the low end, and let your sound cut through better, sintead of getting all lost in the mix.
Well I typed a lot needlesly. And I'm quite tired of it. SO maybe someone else can be helpful instead.

Pedals are absolutely NOT required. Chuck Schuldiner used no distortion or overdrive pedals whatsoever (only occasional chorus, according to an interview), and he got a very metalish (imo) sound, just out of his Marshall (solid state, iirc) amps.

To get the sounds of most of Trivium's sounds, could you get those with a BOSS Me-25? I know you can get that sound you hear in their album "In Waves", but what about their other albums?