Be forewarned, a plethora of spoilers abound.

Here are my picks in no particular order.

Yu Yevon from FF10. This is mainly due to the fact you can't die.

Sephiroth from FF7. All you needed here was debarrier and knights of the round or omnislash.

Dr. Wily from Megaman 3. His last form was just a matter of flying directly above his head with the rush jet, and switching to top spin. One hit and he's all done. This would prompt Capcom to fix that in RockMan Mega World on the Genesis/MegaDrive. I've beaten this game several times, and had no idea about the top spin until recently.

Kefka from FF6. Evil clown turned bloody angel who can be dropped

Bowser from SMB3. He pretty much kills himself. Need I say more? I suppose the depression from being beaten by the plumbers had finally come to a head.

Olga Flow from PSO. Again, need I say more?

Dr. Robotnik from Sonic 2. In spite of having no rings throughout that stage, this fight is pretty easy.

Carltron from Secret of Evermore. This one was just more long than it was anything else. You just needed the formulas barrier and energize, a maxed out attack level for your dog, and enough bazooka shells. The dog does some insane damage at full power, especially in toaster form.

The Mana Goddess from Legend of Mana. Hell, that whole game was pretty easy.

Dracula from Castlevania 2. Gold knife=PWN3D!

Not to ruin it for anyone, but the last boss (or bosses) in ffx2 seemed easy to me. I remember it took me 4 hours to beat Sephiroth in ff7. DOn't get me wrong, FFX2 has some pretty hard bosses (I spent 5-6 hrs on one alone). Then again, it could be the fact that I was like almost lv70 when I took him on, and my dark knights' darkness ability really came in handy, but I still think the boss was kind of easy. I still have to beat it again to get the perfect ending.

I can't really think of any others besides the obvious ones because I was into PSO too much before ffx2 came out. True enough, Yu Yevon was easy, but the final aeon or Tidus's father was hard as heck. Took me a few times to beat him.

Yu Yevon is #1 on my list...

Then the last boss of Final Fantasy VIII made me laugh as a tore her to shreds... she was so darn easy (With Aura and Lionheart of course )

i remember the end boss in contra to be a snap. you spend all that time running the gauntlet of that last stage to fight this retarded alien hive thing. a poor man's mother brain (but not that horrid mother brain with lipstick and eyelashes from that awful nintendo power hour cartoon). big deal.

The easiest boss i would have to say FF7, sephiroth, just mime 2 Knight of the round and he is dead.

All the rpg related bosses are only tough in relation to your level range and character developement. I can't think of any hard non rpg bosses, because as time passes you understand the bosses strategy and they no longer become a challenge.

FFX spoilers:

Yu yevon is the easiest boss, because you can't DIE. Jecht is supposed be the "real" final boss, though.

OMFG Dragon is such a wimp in PSO. Even a level 1 could beat it.
Level 1 = supreme newbness.

Pretty much any modern console rpg has easy bosses.

I don't think you guys should count those bullshit RPG "real boss but its kinda a story part so its super easy" bosses. They are SUPPOSED to be easy as hell, and are just there for dramatic purpose. And like HC82 said, RPGs bosses are almost always difficult based on your charater levels, so if you speed through the game, they can be challenging, but if you putz around with no live leveling your Knights of the Round materia or whatever then of course they are easy.

i think the easiest boss, was Devil May Cry's final boss, it didnt even take me but at the most 10 minutes and i beat it (renting the GAME) i rented it and beat it in 3 days.. so ya i think he was pretty easy.

I think we're all agreed that FFX had the easiest boss. You couldn't really lose to him anyway. >.O

DMC had a pretty simple boss, but it got kinda rediculous on DMD mode.

Megaman Zero had a pretty simple boss that didn't get hard until Ultimate mode, but then, everything was killer in that mode.

PSO, Olga flow can dish the damage out pretty evillishly (MY WORD! No takey! ^_^ ) but he goes down quickly.

~the last boss in Trojan (8-bit Nintendo, Capcom) - i remember going through this game & powering up just to give the final boss a critical beating.. =)

Playing Metal Gear on the NES (never played the MSX one) the other day, I was reminded of Big Boss and how if you moved a certain way, you could get him stuck spinning around in a corner and just unload your rocket launcher on his ass.

Sephiroth was a pushover. Also, Dagroth, or whatever his name is, from Morrowind: The Elder Scrolls III, was also a joke. ...Or maybe I just raise badass characters.