Hi Mark,You'd alienate far fewer than 1% of your visitors - add a text alternative at the bottom of the page and everyone is happy (this should be done anyway). Personally I like using the drop-downs for sections and the left bar for main pages. Enough people use the Microsoft site and others with similar navigation - I don't think the drop-down idea is particularly foreign to visitors.
DHTML won't work in pre NN4.7 browsers and pre MSIE4 I believe, but don't quote me on it. Those users will just see the background colour of your cell and no error message.
Cheers
Andy
------------------
Internet Business Solutions S.L. (Spain)
Dreamweaver Users Forum