<!–– [if gte IE 6 & lte IE 8]> ––>

It seems it was down to caching – I’ve updated the post.

I’m sure that the HTTP header thing will be reliable (in IE8), there was such a big fuss about it.

However, check that page just before/after IE8 goes mainstream, as if Joel Spolsky is right, they will have reversed the default (so that IE8 renders as IE7 by default).

[if (IE 6)|(IE 7)]

[if gte IE 6] nested within [if lt IE 8]
———–
Followed by:
———–
———–
The following script will show the rendering version Internet Explorer thinks it is:

So:
* All the IE6 tests work correctly, displaying the text
* All the IE5 tests work correcly, displaying nothing
* The ‘compatibility mode’ Javascript isn’t displayed, because document.mode is IE8 only. document.compatMode should work in IE6 + 7.

There’s an interesting MSDN article which talks about setting HTTP Headers which can control IE’s behaviour: setting ‘X-UA-Compatible’ to ‘IE=7′ should make IE8 render as IE7. I’d love to know if that were reliable!
source: http://msdn.microsoft.com/en-us/library/cc288325(VS.85).aspx