It really depends on the Search Engines when it comes to how much weight each element has when it comes to optimization.
Some search engines put more emphasis on links in and out, some on page content, others more on meta tags, but its usually a balance between all of them that makes the algorythm.
I think Meta tags should always be used, simply because it’s how pages and content are classified and looked up in an intranet (sorta like a librairy index card, it includes more or less the same details as a meta tag.). Plus, it can be what tips the scale in your favor, versus another site that does SEM but doesn’t focus on clean metas.
As Joe says, you have to forge your own experience. This is an aspect of marketing that is both an art and a science. My own experience has always been clean html (w3c.org compliant), compressed js, organised metas, organised and well written content, site map and a good network of links is the key to success for web sites.
But gambling is such a cutthroat one…
That’s my old school $0.02.