My email and hosting provider's (ukfsn.org) spam filter is not particularly effective any more so I've outsourced the task to Google mail. I like Google's mail app, but I don't want to be reliant on it. I don't want to have to abandon my email address or stop using my favourite email client. Fortunately Google have made gmail flexible enough for me to use it completely transparently. I've configured ukfsn to redirect all my email to my gmail address, and gmail to allow my PC to fetch email over the POP3 protocol. Another useful feature is the 'Send mail as:' option in gmail settings. This means I can log on to gmail and still send email from my preferred email address, rather than the gmail address. Useful when I'm away from my PC.
The spam filter is working nicely. No false positives yet. I just need to import all my filters to gmail to seperate out all the mailing list posts, and at some point I might want to figure out how best to upload my email archive.