Historical, fantasy, magic, horror, supernatural, survival, vampires, demons, pirates, mutants, ghosts, romance (FxF, MxM, MxF) (Romance should be part of the plot and not the whole plot in itself), etc.
My computer, yes. As with what Rina said... it's pricey, but it's been completely dependable without issue for about five years now.
I'll admit that I buy my cats pretty nice cat food. Not ridiculously expensive, but certainly a fairly high quality food. Because I love them and I want them to be healthy.
I don't consider books, because I refuse to buy hardback and tradepaper. Which is what I constitute as "spending extra money". Otherwise, necessity. >> <<
Food/Groceries. XD I'm not one of those "omg only brand name things!" but, we eat REALLY well. I make almost everything fresh from scratch and I make sure there's seconds/extras left over in case someone comes over or someone wants more. I like to make sure we have plenty of snacks, sweets and drinks in the house too.
I'm working on trying to spend leeess on groceries. @____@
Touhou paraphenalia and artwork. Someday when I have my own place, even when I'm impoverished I'll be spending money on touhou and artwork. Posters, plushies, hand-stitched dolls made from recycled material (my favorite)...
Seriously. I don't draw often per say, but when I do, I only use high-quality art products. My favorite mechanical pencils are $10 a piece, sketchbooks the same, and regular pencils are twice that. My tablet was $100 and I'm pissed cause I couldn't get the $2,000 one. I'll pay for Photoshop when I have the money too.