Strategies for pages / posts with multiple content regions

I’m looking for strategies for handling sites / templates with more than one dynamic content region on a page.

SCENARIO:
I have a two column layout. The left column is a “content” column and the right column is a “media” column.

OBJECTIVE:
Using the admin panel, what’s the best way to get photo_A and photo_B in the right column of post_1. I want the client to be able to do this on their own posts/pages so hard coding the template and using HTML mode in the editor is out.

TEMPORARY SOLUTION 1:
Use CSS to float images off to the right side bar:

.entry img { float: right; clear: right; margin-right: -200px; }

TEMPORARY SOLUTION 2:
Absolute positioning which is even worse in my opinion.

DESIRED SOLUTION:
In the write/manage tool define a second editable region so “content” goes in one editable region and “media” is added to the second editable region via the Media Gallery.

Thanks,
David S. Webster