How important is it for key phrases to appear earlier on in code?

For optimum ranking ...

[vmaster]

Although my key phrases VISUALLY appear towards the upper half of the viewer's screen, they do tend to be lower down in the actual html code, thanks to the way the site is structured with tables and columns - since I have a left navigation column, all its contents appear first. How important is it from a ranking perspective for the key terms to appear early in the html code?

[heini]

Apart from the question for how much onpage criteria account anyway I'd say it's plain common seo logic to make important phrases appear higher in the code, as well as in headers. Never sure about the value of having it at the bottom of the code too.

To overcome lefthand navigation problems you should perhaps be looking at this:
[webmasterworld.com...]

[Nick_W]

And if you're feeling particularly brave you might like to see what folks had to say on CSS and SEO [webmasterworld.com] ;)

Nick