1) Total number of books owned?
No clue. I have a database that I'm supposed to be entering them in, but I haven't gotten very far. Nor are all of them currently living with me. Best guess, probably somewhere between 750 and 1000, not counting Young Adult books that are boxed up waiting for my Hypothetical Future Children - who, most likely, will probably be as uninterested in the Baby-Sitter's Club as I was in all my mother's horsey stuff.
2) The last book I bought?
Possibly Bulfinch's Mythology. Possibly Therapy by Jonathan Kellerman. Nothing very recent, because I've been good.
3) The last book I read?
I'm re-reading A Clash of Kings by George R. R. Martin.
4) Five books that mean a lot to me?
Cyteen by C.J. Cherryh
Memory by Lois McMaster Bujold
The Last of the Really Great Whangdoodles by Julie (Andrews) Edwards
Rite of Passage by Alexei Panshin
The First Man in Rome and The Grass Crown by Colleen McCullough - along with the rest of the series, but the first two books in particular.
5) Tag 5 people and have them fill this out on their Ljs:
I don't like requiring things of others... But I'll take volunteers.