Alright, having gone through all of them here are my thoughts, which are all contingent on there artwork being properly scaled for the multiple formats we'd need them to be:
Advos
Logo: I like the idea of the design, but I can't immediately tell what it is at a glance. On the surface it just looks like a keyboard and doesn't scan as "NSM". If someone like me can't tell what it says right away, newer or even frequent guests might not be able to either.
fi_le
Banner: I like this one, it has a warm feel to it and the potential for variation using different characters and music as the background. That said it's a little busy and the site name is scrunched into the top right corner when it really should be the primary feature.
KC Symphony
Banner 1: This one is fun, possibly a good choice for a night-mode banner, but the lack of the site name really hinders its effectiveness. It's difficult to imagine having the name without sacrificing the overall cohesion of the piece. I do like all of the details, however, but given the scale needs to be variable, I'm not sure how visible or clear they'll be on some screens.
Banners 2-5: This one is much more on brand with the piano front and center, which makes up for the lack of site name. The alternate backgrounds would be nice to cycle through, and I especially like the Super Mario inspired one, but that may be my personal bias.
Banner 6: This one is cute, but unless you know what the site is you'd have no idea what the characters are doing or looking at. Sure you have conductor Kirby off the the side and some music notes around, but they seem incidental and if you're looking at this with no knowledge of what NSM is then you're likely not going to figure it out based on the banner alone.
Logo 1-3: This are super neat, and I appreciate the variations so would could play with them to see which pop better on different backgrounds, or perhaps that's to recreate the flashing effect. The throwback to the NES era with the Super Mario Bros inspired font is a great touch and the folder icon seems like it can be utilized for a number of things. That said the way its organized seems a little bulky, perhaps we could separate the elements for different uses.
Sir Bone
Banner 1: This one is hard to look at because the colors seem haphazard and just garish.
Banner 2: Now this one is cool. I like the minimalist/post-modern design of the characters, is makes the banner pop more and you could spend a minute or two just looking at it to figure out who's represented there. Personally I'd like to see a version of it without the site name to see the details behind it, but as it is this is probably may favorite of the submissions.
Logo: This logo is alright, but it doesn't have any personality. It just feels so bland, especially compared to your banner art.
With the above commentary, I think I'd prefer Sir Bone's second banner with KC Symphony's Logos together. To my eye they flow well together with a little editing to match the fonts and other details. That said we can always trial them and let the public vote on them each.
