1) Total number of books owned?
This is really difficult to answer. I'm guessing when I say that between
2) The last book I bought?
Gate of Ivory, by Robert Holdstock. I think this means I now have all the books in the Mythago Wood set, but more keep appearing, as seems appropriate for the series.
3) The last book I read?
Currently reading the above; the last one I completed was The Hollowing, same author. Excellent book, though I mean the series more than the book in particular; it's very hard to know where one ends and the next begins afterward.
4) Five books that mean a lot to me:
Guh. Ok.
Lord of the Rings (JRR Tolkien), because it really got me started on this 20-year fantasy kick, which shows no sign of ending, ever.
The Lion, The Witch and the Wardrobe (CS Lewis), because it's the basis of a lot of concepts and notions of story for me. It's been brought to mind lately, of course.
Zen and the Art of Motorcycle Maintenance (Robert Pirsig), because it's contributed so much to who I am.
Adventures of Wim (Luke Rheinhart), because it showed me that any religion without a sense of humour is not all there.
This last one is difficult.
Wyrd Sisters (Terry Pratchett) barely, just barely, only barely, beats out Magician (Raymond E Feist), because I bought the two of them the same day, and they began the real process of buying books for myself. But Pratchett has lasted better as a writer than Feist.
5) One book you think the world would be better without.
[There was a silly tag question here. I killed it. Body's in the fridge.]
I could be very highbrow here, and nominate Mein Kampf, or The Prince, or one of the Watchtower publications, or something like that, but I'm going to go for Gary Gygax' Role Playing Mastery because it completely misses the point. I have a copy, and I take it out and look at it once in a while, because if I had Cthulhu in a box, I'd take him out to look at once in a while too.