i find it easy, depending on the size of the Div tags. say if your building a horizontal menu system, or you you want 3-4 div blocks across your page to display modules, like you would see on a Gaming clan website.
Use an <UL> list...
Code:
<ul class="horzBlocks">
<li><div class="myblock">My content</div></li>
<li><div class="myblock">My content</div></li>
<li><div class="myblock">My content</div></li>
<li><div class="myblock">My content</div></li>
</ul>
mind you, i'm writing this off the top of my head, but use something like the following css code to make that a flat horizontal list.
Code:
ul.horzBlocks{
display:inline;
margin:2px;
padding2px;
}
div.myBlock{
display:block;
float:left;
clear:both;
}
mind you, i'm most likly missing alot of code in that, but the general idea of what i am saying is there...
either this way, or the above stated floats with containers like redShift stated would work.
depends on your preference, and what your trying to do.