Excellent, thank you Larry, this was the boost I needed to get me thinking in a different direction.
My thumbnails are going to be 150px wide and 100px tall, so I've currently got this version of the code you suggested:
Code:
div.post-headline h2 {
display:block;
margin-left:170px;
}
div.post-bodycopy img.wp-post-image {
float:left;
margin-top: -30px;
}
Which works perfectly for post headlines that are one line (and doesn't appear to affect the placement of the image in the full post, which is good).
For post headlines that run over to two lines (and who knows, maybe three), I'll have to noodle around some more. I'm thinking I may have to venture into the realm of absolute and relative positioning, though that may open several new cans of worms. Good thing I like playing with code!
Or, hmm, I could ask the client to try and keep to a character limit on post titles. Would simplify things for me, but not for the client. Heh.
I'm not quite ready to post a link here, since the site is for a client and is still in development. When it launches, I will definitely give the URL.