I must say Japan's is pretty distinctive. You gotta give them credit for sticking to their imperial court traditions with this one. most Country's national anthems are lame marches.

Another one that's got a nice ring is Mongolia's:
http://david.national-anthems.net/mn.htm

And I gotta say, the US's is hard to sing, but it sure has presence, nothing beats an old drinking song!

The defunct Ottoman Empire's one up to 1861 was pretty kick-ass too:
http://david.national-anthems.net/ote.htm

Kurdistan's is just silly:
http://david.national-anthems.net/krd.htm

The illegal Tibetan Anthem is awesome, I think:
http://david.national-anthems.net/tib.htm

And I guess you can't beat the EU's Bechtoven "ode to joy", although it's a little tame. They could have picked something more badass, like number 5 or something.

Mexico's isn't bad as the whole march thing goes, it almost sounds like Rossini:
http://david.national-anthems.net/mx.htm

Bhutan's is nice:
http://david.national-anthems.net/bt.htm