What I am trying to accomplish is having a fixed-width first div and a fluid second div which will fill up the rest width of the parent div\'s width.
To get the first example working, you should also float the containing div, this will make sure that both of the elements within sit as you would expect within it. Not really sure what you mean by 'is a pain', though?
One down side of using table-row (very related to the OP) is that you can't use margin/padding on a row.
You could do something like this. It puts your main content first. You can use a vertically repeating css background image on your main "content" container to create the illusion of a background running all the way down the left column.
<div id="content" style="clear:both;">
<div id="mainwrap" style="float:left; width:100%;">
<div id="main" style="margin-left:100px">
Main content here
</div>
</div>
<div id="leftnav" style="float:left; width:100px; margin-left:-100%;">
Left content here
</div>
</div>
To extend to a 3-column with fluid center:
<div id="content" style="clear:both;">
<div id="mainwrap" style="float:left; width:100%;">
<div id="main" style="margin-left:100px; margin-right:100px;">
Main content here
</div>
</div>
<div id="leftnav" style="float:left; width:100px; margin-left:-100%;">
Left content here
</div>
<div id="rightnav" style="float:left; width:100px; margin-left:-100px;">
Right content here
</div>
</div>
display: table-cell
is perfectly fine to use, with just one downside..
It doesn't work in IE7 (or IE6, but who cares?): http://caniuse.com/#search=css-table
If you don't need to support IE7, then feel free to use it.
IE7 still has some usage, but you should check your Analytics, and then make a decision.
To answer your specific use case, you can do it without display: table-cell
, provided that you don't need the height
to adjust based on content:
http://jsfiddle.net/g6yB4/
<div class='clearfix'>
<div style='float:left; width:100px; background:red'>some content</div>
<div style='overflow:hidden; background:#ccc'>some more content</div>
</div>
(why overflow: hidden
? With: http://jsfiddle.net/g6yB4/3/ vs without: http://jsfiddle.net/g6yB4/4/)