If you usually borrow books, and only own 1, I think your idea of buying books you have already read, liked, and would want to reread is a very good one. It would be horrible to buy a couple of books and find out you don't like them. In my case, that doesn't matter, I own hundreds of books that I love and reread. Owning a few duds is no great loss in the scheme of my bookcases.
Good Omens, By Terry Pratchett and Neil Gaimon.
One of the funniest and sweetest stories of the fight between Good and Evil on Earth. It's a bit of a horror, but I guess it takes a LOT to creep me out that way.
Dead Witch Walking by Kim Harrison. Our heroine is a witch and a private detective. Her housemate is a bisexual female vampire. Their business partner is a pixie (think male Tinkerbell.) They have adventures, and complicate each other's lives. It's now up to a four book series, and our witch has gotten drawn into evil demon magic against her will.
American Gods by Neil Gaiman. Dying Gods, no longer believed in by modern humans, trying to resurrect themselves any way they can. The good, the bad, and the ugly.
Since you are borrowing: the Anita Blake, vampire hunter series, by Laurell K Hamilton. The early books are stunningly good thrillers. Lots of excitement, adventure and gore. All sorts of supernatural beings. As discussed in another thread, the later books just turn into non-stop erotica. (I cant call it ****, because all the participants have personalities and their own motivations.)
Foucault's Pendulum by Umberto Eco. This is much more meaty than The DaVinci Code. Chock full of secret organisations and conspiracies. Full of religious, metapysical and literary allusions. This is serious literature by one of the most respected academics alive. Expect real life to triumph over the adventure.
The Black Jewels trilogy by Anne Bishop. Well. Just chock full of sado-masochistic erotica involving demons and evil witches. Personally I think the very last chapter in the trilogy is incredibly weak. But I cant complain about the intensity of most of the rest of the story.