Worst and best languages for singing?

Montserrat Caballe is Catalan like me, hence Spanish. Also she is very patriotic and proud of being Spanish.

worst: Italian, Spanish, Portuguese
best: Swedish, Scottish Gaelic, Finnish

I have recently gotten into Icelandic rock music and singers. Some of these artists are truly incredible.
I want to post a couple examples:

Paul Oscar sings "Sama hvar þú ert" (Somewhere You Are)

http://www.youtube.com/watch?v=5s_etTu0sjc

Greifarnir sing "Hun Er Svo Saet" (She Is So Cute),

Best: English, Spanish and Italian.

FRANçAIS CELINE DION BIEN SûR!

http://www.youtube.com/watch?v=Qdjt0mWWH_M&feature=fvw

Gibberish: http://www.youtube.com/watch?v=oavMtUWDBTM

Oh please, stop lying Franco, you are mexican trying to be catalan

Altai: http://www.youtube.com/watch?v=NRBW6ywjXWo

Kazakh: http://www.youtube.com/watch?v=rX0OPBKtSmk

Kazan Tatar: http://www.youtube.com/watch?v=oNTJYZksEUs

Kazakh: http://www.youtube.com/watch?v=OZu1WMEiR3I

Buryat: http://www.youtube.com/watch?v=P9Zh-GPEY40

http://www.youtube.com/watch?v=2VBozS5cMeU