Its pretty easy to find the most powerful pokemon.All you have to do is find the pokemon with the best overall stats and you have a winner.
AND! Dialga is teh ultimate pwnzor of the multiverse!
dragon-steel.... it doesnt get much better than that!
in my opinion, steel is more powerful for general combat than dragon!
If you play your types right, u can beat pokemon 15+lvls higher. i beat the elite 4 and champion when my highest lvl pokemon was lvl 52 (at start) and 54 by the time i got to the champion.

So just use your brains people!
you have them for a reason!

and out of the 3 3rd gen starters when they r fully evolved, swampert has the lowest stats.

and you can get up to 12x damage if you play your types right (hold items, crits ect)

All of my pokemon are level 100. here's the pokemon i use (sorry, one is legendary)
#1-Vaporeon:substitution, ice beam, psychic, surf (substitution is uber effective. it makes you invincible for like 7 turns. Which for me lasts the entire battle.)
#2-Charizard:flamethrower, dig, cut, thunderpunch (all are extremely powerful moves, and thunderpuch would even take out a lvl100 Blastoise easily. plus it helps that charizard has one of the highest attacks)
#3-Mewtwo:psychic, recover, psybeam, icebeam (i personally don't like to fight with him because he has an extremely low health and his moves run out really fast so i have to go to a pokemon center even when i have full health)

I also have 2 venesaurs, 2 blasoise, 2 zapados, 2 articuno, 2 moltres, magmar, pidgeot, jolteon, flareon, luigia, ho-oh, 2 snorlax, hypno, victrebell, tyranitar, alakazam, etc. that all have amazing stats... while alot of these are legendary you'll very rarely find stats that are better than them. plus... the only reason you wouldn't want legendary pokemon on here is because you couldn't catch them. Oh yes... machamp is also one of my favorites ever since i saw the episode where charizard fights machoke and does submission and owns his@s$. plus the last gym that ash fought in the original pokemon was the boss of team rocket who used machamp.

Mines is my adamant salamence as it has the highest possible attack power

My lv.84 Lugia.

AEROBLAST!!!

My dark Aerodactyl's ancient power to charizard = 936 hp damaged

Charizard or Mewtwo
(The ledgendary dogs aren't considerd rare on this games so them to).

LOL, topic poster said a Legendary as the strongest Pokemon.

FAIL.

my lvl. 100 magikarp is THE strongest pokemon i have ever seen EVER it will splash you to death.......LOLOLOLOLOLOLOLOLOLOLOLOLOLOL

Shuckles hands down the best pokemon.
Move Set:
Toxic
Sandstorm
Double Team
Rest

Item:
Mint Berry

Shuckle can have 614 Sp Defense and Defense at Level 100 so a super effective attack will only do around 3 dmg. then you just toxic and sandstorm to death while double teaming. If you get low HP rest and mint berry will instantly awaken you.

Ditto.

I mean, seriously. Your just walking along and BAM a Ditto jumps out and turns into a FECKING STEELIX. Your totally scee-rewed

Seriously? In my personal opinion its either my earthquaking Meganium or Red's Pikachu. That thing was strong.

well at I defeated the elite four with my pikachu at level 72......

HP.......... 170
ATTACK...... 115
DEFENSE..... 103
SP. ATK..... 110
SP. DEF..... 102
SPEED....... 194

MOVES:

THUNDER
RAIN DANCE
QUICK ATTACK
THUNDER WAVE

Yes, but a DITTO could BECOME your pikachu.

Therefore, Ditto is techincally the strongest pokemon. I can change into any pokemon.