i'm using Oulipo on these two themes:
http://ninblogs.wordpress.com/ (don't use the css upgrade for this theme)
http://htda.wordpress.com/ (no css upgrade)
first of all, i simply love the new theme, it's exactly what i was waiting for :) but there's one thing that makes me wonder if it's on purpose or not, and that's the way images are positioned.
every image is automatically centered, which won't allow to put two or more smaller images side by side. using the gallery function is no option, since i need full control over size and position of the images. please take a look at this post with images, of which the first two were sitting side by side with all other themes i had before. now every post with this layout is destroyed.
http://ninblogs.wordpress.com/2008/11/12/flickr-bell-centre-montreal-qc-111208/
the opposite is with images with captions. they won't center until i put them in <div align="center"></div> tags, and as soon as i edit the post (no matter if WYSIWYG or HTML) it's just `<div></div> and they sit on the left again.
i really hope the automatic centered images are not considered a plus of this theme and you consider to change it back to "normal" behaviour, because imho they just hinder the user's ability to style a post as he sees fit. that's espacially sad since Oulipo is in every other aspect just perfect for photo heavy blogging.
oh, and sorry if something makes no sense, my english isn't the best...