On ff.net, there are 111 pages of Xander fics, 323 pages of Spike fics, but only 20 pages of Xander/Spike fics. For comparison, Willow has 94 pages out of 1152 total.
Obviously, the precise ratios will differ in different archives and not all ff.net fics are correctly labelled, but it looks like Xander-centric stories are a respectable chunk of the fandom, and the majority of them aren't Spike/Xander.
I don't know off-hand of any stories centred on someone else's Halloween experience, but then as the only main character to end the show nominally normal, he's the one who most in need of a power-up - or so it would seem, quite falsely, to the many authors who don't get the point of his character.
Obviously, the precise ratios will differ in different archives and not all ff.net fics are correctly labelled, but it looks like Xander-centric stories are a respectable chunk of the fandom, and the majority of them aren't Spike/Xander.
I don't know off-hand of any stories centred on someone else's Halloween experience, but then as the only main character to end the show nominally normal, he's the one who most in need of a power-up - or so it would seem, quite falsely, to the many authors who don't get the point of his character.