I've always considered spitting to be a disgusting habit and was raised in such a way as to very rarely do it unless strictly necessary. I had a discussion with a friend earlier this morning after she looked on with disgust at a guy walking down the street and noisily spitting onto the pavement. It narrowly missed hitting someone else and they muttered something angrily under their breath.
Personally I'd only do it if I really had to clear my mouth of a vile taste and even then I'd try and make sure I did it somewhere subtle like in an alleyway. I certainly wouldn't spit near anybody else. I take my oral hygiene very seriously though and so I've never really felt the urge the spit unless I've eaten something with a horrid taste.
So to cut my rambling short, do you spit or do you swallow? Feel free to elaborate as to why!