frames, iframes and noframes

[Elemental Thought]

I was wondering if anyone knows the specifics on iframes vs. noframes for google. I've got some iframes, which of course are not good for SE's. However, they contain in one form or another most of the content of the site. So, some examples I've seen do this:

<iframe blah blah>
You can't see iframes
</iframe>

and other examples I've seen do this:

<iframe blah blah>
<noframes>You can't see iframes</noframes>
</iframe>

Theoretically these are the same things, but I wonder how google and other search engines handle them. Is google likely to ignore any content between iframe tags unless it's got the noframes tag attached? I was thinking a third alternative would be

<iframe blah blah>
</iframe>
<noframes>
You have a really lame browser.  I mean... uh... here's some content.
</noframes>

Any experts out there have an opinion on this?