Hot DCSS Spell Poll Results
Votes for best level 1 spell were pretty diverse, but Animate Skeleton was the clear winner.
Worst level 1 spell was easier; most people picked either Corona, Sting, or Infusion.
My votes were: Summon Butterflies best, Corona worst
Blink got the most votes for best level 2 spell. I had no idea it was that popular. As you can see, most other people voted for Sticks to Snakes, which I did expect.
The great thing about Slow and Corona is that even when they're worth casting, you'll hate that you're casting them.
My votes were: Sticks to Snakes best, Song of Slaying worst
I never would have guessed that Regeneration would place so highly here.
In contrast, absolutely anyone would have guessed that Gell's would "win" the title of worst level 3 spell. Maybe there are worse level 3 spells, maybe there aren't, but Gell's is the punchline for bad spell jokes.
My votes were: Conjure Flame best, Inner Flame worst
Early responses for best level 4 spell were almost 100% Summon Lightning Spire, but it diversified later.
I've defended Leda's in the past as not being as bad as people think, but it's still probably worse than the other level 4 spells.
My votes were: Summon Lightning Spire best, Leda's Liquefaction worst
BVC got the most votes for level 5 spell by a huge margin, which I fully expected (even though I disagree with it).
Agony got quite a few votes for worst level 5 spell. This is gonna be the one occasion where I make fun of your votes. If you voted for Agony as worst level 5 spell, you're silly and I'm making fun of you.
My votes were: Lee's Rapid Deconstruction best, Alistair's Intoxication worst
I didn't have a guess for what the results of this one would be. There are so many weird level 6 spells.
My votes were: Deflect Missiles best, Ozocubu's Refrigeration worst
Malign Gateway was at like 70% for a while, but in the last few days of the poll it plunged.
Another "worst" result that anyone could guess. This is extra funny if you know that Ring of Flames used to be level 8.
My votes were: Malign Gateway best, Ring of Flames worst
I expected Borgnjor's to get the most votes for "best" here. I was very wrong.
Man, level 8 has a lot of bad spells.
My votes were: Death's Door best, Necromutation worst
This one is interesting because Shatter had a big lead in the early responses (even excluding mine), but Fire Storm crushed it in the final results.
Tornado managed to occupy almost the exact same space in both the best and worst charts, somehow.
My votes were: Shatter best, Glaciate worst
(edit: this image originally had the wrong number for Fire's "worst" votes, it's fixed now)
Sort of paralleled the best level 9 spell results; Earth was winning at first but then Fire came from behind and overtook it.
I expected either Ice or Fire to get the most votes for "worst" here, though I wasn't sure which. Didn't see this coming. I do personally think Ice is better than Air though. I think that I won't include these questions in the next iteration of the poll, if there is one, as elemental school balance has been steadily improving.
My votes were: Earth best, Fire worst
There's also a single image version of the results if you want that.
Thoughts on the poll
I think this poll suffered from the way I divided spells. Compared to a single-school spell, a multi-school spell of the same level is harder to cast, which inherently makes it worse - so it probably shouldn't be in the same category. Spells that can be used out of combat, like Animate Dead, Deflect Missiles, and self-enchantments in general, are a similar issue.
I intentionally left the meaning of "useful" vague, because I didn't want my own ideas about spell strength to influence the results (aside from my 1 vote in each question obviously). But as nago pointed out in the original thread, this does have its issues - some spells are much more useful in "turncount runs" compared to "winrate runs", such as Regeneration and Statue Form. Dividing spells by level was intended to minimize the contest between "early game" and "late game", but some low-level spells remain useful for much longer than others. And some spells are useful for a greater variety of characters than others.
If I do something like this again next year, I should devise a different scheme to divide up spells, ideally one that produces fewer than 9 categories.
Randomizing the order of the questions would help with bias but it would also make the poll a lot less convenient to answer.
It is trivial to pollute a poll like this with bogus responses, but I didn't see any obvious foul play, which was a pleasant surprise.
That said, please don't use these results to inform your own beliefs about how good a spell is! You should always evaluate such things for yourself.
Other pointless observations
The spell schools to have no spells winning a "best" poll were Charms, Hexes, and Ice Magic.
The spell schools to have no spells winning a "worst" poll were Air Magic, Conjurations, Ice Magic, and Necromancy.
Clearly, this proves that Ice Magic is the most balanced spell school.