Yeah they do sound similar. great songs.

http://www.youtube.com/watch?v=LBna1sm6XhY

One of the most awesome final boss themes ever.

That reminds me that I think this is a good song, too (pretty sure this qualifies as a boss theme) http://www.youtube.com/watch?v=_UGKCvIrF_o

Xenoblade's main boss theme is awesome.

My all time favourite epic Boss theme was from Dragon warrior 3

http://www.youtube.com/watch?v=18fqfGcr3PI

but nowadays we do get some really good boss battle musics, a notable example is Ni No Kuni

http://www.youtube.com/watch?v=kVVlOXlctmo

and another game which has an amazing soundtrack overall is the PSN game shatter, sometimes i play it just to listen to the music

http://www.youtube.com/watch?v=lVONzZdMFuQ

as for some good potential boss battle music i can only think of this

http://www.youtube.com/watch?v=mmfcvG_lLxI

Western games took over and people rarely play the Japanese titles anymore. When Japanese games were on top Soundtracks were key.

Oh, have I got boss music for you. anyone hear of... eartbound :)
http://www.youtube.com/watch?v=t4z82byt5mA

I agree, I miss the old MIDI boss tunes of the good old days.  While movie score type music is fine for certain games, not every game has to try to sound like a Hollywood epic.

I think the last truly memorable boss theme I can remember was during the Shadow Queen battle in Paper Mario: TTYD...

If you're not hearing awesome boss music in recent games, you're not playing the right games, although I'll agree that good boss music is severely lacking in comparison to past gens where music was comparatively as good as gameplay and story..

Yakuza 3

http://www.youtube.com/watch?v=5DrEn-DEqvE

http://www.youtube.com/watch?v=AgAQYPa7s-A

All the boss music is pretty good, but these are the best. Fly is actually both the final boss and the intro, each one is cut a little bit different in the game though, but they're both from the same song. This version is the one plays during the fight with Mine.

Yakuza 4

http://www.youtube.com/watch?v=OnrTJqDu6FI

Yakuza 4's final segments are possibly the most badass things to ever come out of a video game. The story, the setting, the music, and the fights themselves helped tie it all together. Each battle also has different music, so it's a new track with each ass kicking you're about to deliver. This track is a mix of all the pre battle and battle music in that scene one after the other. Comes around to 12 minutes.

I also liked that Xenoblade song that was posted.

Phantom brave : http://www.youtube.com/watch?v=TrtN-6FKii4