I feel like gmail catches 99% of the spam I get. Also I unsubscribe from a lot of it if I get any. I definitely get a lot of spam though.. registered on way too many sites lol. Think I've got around 100,000 blocked email addresses on gmail at this point and the spam keeps coming.
I also always found it kind of weird that e-mails for things I signed up for, like e-mails from the official SpongeBob fan club from Nick, had always ended up in the spam folder of my e-mail for years.