Congratulations Ozbenno, yet another trophy to your collection!
My verdict on the songs:
101 - Metro Station. Never heard of. Looking at wikipedia, the song Shake It was released as a single in the US, Canada, Australia and New Zealand, nowhere else. Surprised - not. Mainstream - not.
102 - Monty Python. Did anyone actually miss this one? The only song rightly categorized as easy.
103 - Silverchair. Never heard, but I googled the lyrics.
Released in the US, Australia, New Zealand and the UK. I agree with HC that this was pretty decent though.
104 - APC. Yeah I know the band, mostly because I know Tool. Never heard of the song though, and to call APC mainstream...
105 - Goo Goo Dolls. I've vaguely heard the name. Single released in the US, Australia, New Zealand and the UK. Am I starting to sense a pattern here?
106 - Phil Collins. I should have known this one obviously, this was the only :suicide: of the lot, as I knew it would be. But I don't agree it's an easy song to guess, especially with that hard clip.
107 - Muse. I knew this song, but Muse isn't mainstream by a long shot.
108 - Bloc Party. I knew this one too, but Bloc Party certainly isn't mainstream either.
109 - The Ink Spots. I knew this only because I know BL, and we've talked about it before. If you didn't get it already, it's the promo song for Fallout 3. And even if you knew about that, it wasn't an obvious clip.
110 - Linkin Park. Of course I know the band, but never heard of the song. It was released as a single in the US, the UK, Germany, Ireland and Switzerland. I guess you could know it if you owned the record, but such a song doesn't belong in the "easy" section.
201 - RHCP. Know the band of course, never heard the song. I'd say it's rightly categorized though, huge band with a less known song is "medium".
202 - Bobby McFerrin. He was the obvious guess, and I did get it. Also rightly categorized I'd say, since it's such a distinct sound.
203 - Enter Shikari. Never heard of, single only released in the UK where it topped at 146. Definitely hard.
204 - Groove Armada. Never heard of, but they seem pretty well-known so I can guess that it's just not my style. Probably rightly categorized.
205 - Keane. Never heard of. Single released in the UK, Ireland, Germany, Netherlands and France. Medium is the lower limit.
301 - Familjen. I think I've heard the name some time. Never heard any of his songs though, and definitely not a million times like you suggested. Album released in Sweden, Norway, Denmark and Australia(!). Definitely hard, but I never had a chance.
302 - Underoath. Never heard of, album was only released in the US, though some other songs from the band have been released down under too.
303 - Motor Ace. Never released anything outside Australia and New Zealand.
So all in all, a whole bunch of hard songs, maybe 4-5 medium ones and 1 easy.