My #1 would be Frightened Rabbit - Pedestrian Verse. Can't get a copy for less than $300 and, although it's not the band's best album, I feel like the last 4 FR albums are all Essential and it's the only one you cannot get freely. I would be fine with black vinyl, but if they were going to make it color I would think a nice blue/green swirl would fit. Also, work with Scott's brother and make a percentage of the proceeds go to the Tiny Changes charity set up by his family. NO LINER NOTES BY A VMP STAFF MEMBER! Pehaps they could get an essay from someone close to Scott as the Magazine article for this one.
Worst? For essentials? I don't really know. There's nothing they could make that would actually offend me. Oh wait, what's that punk band where the singer turned out to be a pedo? Yeah, never do anything regarding that band.
Bonus could be the original silk-screened cover as an art print. Kind of like how they did a lenticular version of the cover for Flaming Lips.