Tarot is also far older and more legendary (in Finland) than Nightwish. The band was formed back in the mid-80's and was one of the first Finnish heavy metal bands.
http://en.wikipedia.org/wiki/Tarot_(band)
But as for covers, what really annoys me is that almost all metal covers are 1:1 carbon copies of the original. That sucks donkey dick and serves no purpose whatsoever. It reeks of record company orders:
" - Cover this song, it would probably sell some singles"
" - but we don't like the song/band!"
"- COVER - IT! Or we'll find another band who does it"
The only covers I've liked over the original have been:
- The Berzerker doing Carcass' "Corporeal Jigsore Quandary", mostly because I always felt the original was faaar too slowly played. The Berzerker did it at the tempo I always wanted to hear it in.
- Opeth doing Robin Trower's "Bridge of Sighs", since Mike's voice is perfect for that song
- Helloween doing Scorpions' "He's a Woman She's a Man", completely turning the song upside down with the traditional Helloween speed.
- Rammstein doing Kraftwerk's "The Model", again speeding it up completely and with Till's rough vocals really adding to it. One of the few 1:1 songs I've liked, but then again, the original song was done with no band instruments.