Alright then, let's try it album by album.
Fright Night: Fire Dance
By the way, as bland as this album might be, I still like the youthful energy and will for making in it. After all, it was hard to pick up the worst song: there are no bad ones! Not that there are any very good ones either...
Twilight Time: Hills Have Eyes
Never liked that song.
Dreamspace: Thin Ice
The Worst of All Stratovarius.
Try to beat that someday! Don't.
Fourth Dimension: 030366
I seriously thought of going with Lord of the Waisteland, but I dunno... 030366 ain't that bad even, it has its own creepy personality. Still it IS the worst of the album though.
Episode: Will the Sun Rise?
Basic, nothing special. But mind you, there are no bad songs on this album.
No bad songs here, either. Had to big one. This one is catchy but a little over-the-top appreciation for the fans.
Destiny: Years Go By
Never actually thought about the worst song here; that is, haven't found the weakest link ever. Years Go By is as good as any other album track, but as a separate song it feels such a filler cry the most.
Infinite: A Million Light Years Away
Once again no bad songs, but I've heard this very commercial feeling piece too much so that it rather bores me nowadays.
Elements, Pt. 1: A Drop in the Ocean
At this point, the-last-song-always-has-to-be-the-ballad arrangement began boring me already.
Elements, Pt. 2: I Walk to My Own Song
Maybe the first album since Elements that also has some uninteresting material in it. I don't like the latter half of the album that much, sans Liberty, one of the best songs there are. Almost went with Dreamweaver, a song that's never opened to me, but then I remembered IWtMOS. A rather embarrassing and ridiculous song.
Stratovarius: Gypsy in Me
A basic song, nothing very interesting going on. A solid album all the way, hard to find those weak links, although they are there.
Polaris: When Mountains Fall
See Elements, Pt. 1.