Wow, where to begin...

I loved the boss fight on Buck Bumble (N64 shooter) where you have to face the praying mantis, but I never got past her.  The last guy on Unreal Tournament 1 was pretty intense.  Absolutely loved the emperor boss battle on Project Snowblind for the PS2.  WOW was that a blast!  Shadow of the Colossus was all about boss battles (16 in all), but some of them felt kind of cheap.  Nevertheless, I still loved those boss battles since they really do feel like bosses and have puzzles to them, unlike the boss battles these days that just consist of hitting or shooting them dozens of times.  The Goliath on Resistance Fall of Man gave me a challenge the first time. 

That's about all I can think of right now.  What about you guys?

The cyber dinosaur in Doom 3 was fun/scary. Jecht fight at the end of final fantasy X. Ganondorf from Zelda:Ocarina of time.

Probably my 3 most favorite single boss battles. If you count a boss sequence...I loved destroying Mars in X-Com UFO Defense.

Defeating Ganon in any of the Legend of Zelda games is always a dear favorite of mine.  Ocarina of Time and Twilight Princess I think had the most epic feel to them, when I was a few hearts away from dying my first time fighting him TP and I finally plunged the sword through his chest I got chills and was breathing heavily! haha

Resident Evil 4 had some great/epic boss battles, all of them were top tier

Ninja Gaiden for the xbox had some seriously difficult bosses.  Defeating Alma (after dying 10 times), complete with some of the most beautiful and artistic cuts scenes the xbox ever had, was a joy to behold

The battle with the Hydra at the Beginning of God of War is one of my favorite boss fights ever.

With boss battles, though, the Metal Gear Solid series can't be beat.

Hm, RPG bosses, though . . . Ruby and Emerald weapon in Final Fantasy VII! <passes out>

AAAAAAH!

Those were nasty! Especially Sonic 2.

I was just playing Metroid Prime, and the final boss of that one is just incredible. Mostly because of the buildup throughout the whole game: research notes about experiments on the metroid with Phazon radiation, and how it was growing and had all kinds of defenses and how they were penetrated (basically clues about what it could do, and how it could be killed). By the time you're about to reach it you know you're in for one formidable, scary beast. And the fight was spectacular, clever, and Metroid Prime (the boss) itself was as freaky-AWESOME as they get!

Besides the fact that he was a bit too easy, prolly . . .

YES! A deformed angelic form (pseudo-God) who summons a supernova (!) accompanied by the greatest boss theme (performed by orchestras all over the world) in game history.

Emerald Weapon and Ruby Weapon FF7, truly epic!

Please don't get upset with me, but I found it too easy...there was a pattern to do things and once you got the pattern it was a cinch...at least for me.

As for the OP, my favorite is not so much a particular boss, but a battle...the final mission in the original X-Com game.  It took a long time (two stages) and the setting was dark, kind of eerie.  I had chills the whole time...and it was difficult...for those familiar with the game, the aliens kept taking over my guys.

The first time I played it I started with 18 soldiers and finished with 3...

In Christ,
KP