Is Relevance In SEO Actually Relevant Anymore?

I was just doing some random searches through some of the major SE's and was surprised to see the amount of total spam pages listed in the SERPs.

Because of this im wondering if relevance mattered any more when it came to getting traffic from the larger engines such as Google, Yahoo, MSN, etc?

Do you think the importance of content relevance on our sites has dwindled over time and been overtaken by inbound/outbound linking making it easier for the SE spammers to get top listings?

Regards,

Lee