that you could only beat using cheats, a guide, or advice from someone who already beat him.

I have four on my mind:

Ruby Weapon (FF7, holy christ everyone knows the amount of preparation necessary for this dude.)

The End (MGS3, I fought him 15 times. That's 15 times of him dragging my ass to a shed, and each try took an hour at least.)

Lu Bu (Dynasty Warriors, I was never able to beat him, really. His ass is too hard.)

Mike Tyson (Punch Out!, my brother, who is a professional boxer with catlike reflexes, beat him way back then when I cried continuously every time he knocked me out.)

EDIT: this should've been in the general gaming section. my mistake. 

Do they have to be Sony games?

Obviously.  We are in the Sony Discussion forum, are we not?

Yiazmat - Final Fantasy XII. 50 Million HP and 5 hours of fun, and death!

Omega Weapon - Final Fantasy VIII - Bastard Sword!

FFVIII last boss.

Ultemecia - FF8

OZMA - FF9

Which Dynasty Warriors couldn't you beat Lu Bu in, and in which difficulty? I used to be a DW fanatic, and I remember beating him using a genius strategy. I don't know if it was on the hardest difficulty though.

Screw it being in the PlayStation section. This should be in general gaming.

Anyways, the 3rd boss in Metroid Prime 2: Echoes in which you get the boost ball from. Ing Guardian was his name I think. Took me 20 times to beat him.

So sad it took you that long to beat The End btw, you can kill him instantly right after the cutscene ends :)

I have an epic story about the last boss, well i think it's epic. I had Selphie in my group and had her slots going and it think her best spell was "The End" well i was on i guess the fourth form, if that is the last form, and it was taking forever for me to kill her or it or whatever. Most of my characters were dying and i didn't think i was going to win. So i thought i would just have some fun because i knew "The End" would not work on this boss. But i always thought The End was pretty so i used it. And it totally amazed me when The End work it was soooooooo awesome because it is the coolest move with the sun shining the green field and flowers and then those two words, The End. And it was i beat the boss i wish i could have recorded it. I tried it again later but it didn't work i guess i was lucky.

This could be a spoiler for MGS4 if you haven't played it. Well it's only a scene, but i guess if you don't want to know anything about it don't read.

Does that long hall way at the end of MGS4 where you are being burned to death basically and you have to tap the button real fast count as a boss. Because that was hard. My finger got tired.