See my post
here for my views on NTL filtering spam.
The main problem is where you use your email address on the web - forums, web pages and particularly newsgroups. I have different email addresses for different purposes, so for example, I have an address that is my real name and it receives no spam because only a few people have it and it's only used on my CV. For websites I don't trust, webpages and newsgroups I have a spam trap email address that forwards to my main address. I have Spampal configured to assign 200 points (500 being the level at which an email is tagged as spam) to any emails sent to the spam trap address. Every now and then, when spam is becoming excessive, I delete the email address and create a new one.
In short - it's possible to manage spam yourself and keep the number of emails you receive to a reasonable level. The people who have problems tend to be those who have one or two addresses and use them willy nilly. That said, given time spammers will find your email addresses, especially if they're simple and use words in the dictionary, perhaps with numbers app- or prepended. That's happened with my two main addresses and there's little I can do except filter out the spam, but it's not excessive.