Setting your blog to private ("Only people I choose" or "Only blog authors" can view the blog) AND classifying it as Adult Content causes login problems when members attempt to view the blog. To workaround this issue, simply turn off one of these options.

Blogger Play isn't showing any images in Firefox. This affects both play.blogger.com and the iGoogle gadget.

Update, 1/28: This has been fixed.

The "create a link" link for Backlinks is currently missing.

Some templates have slight layout issues when used with right-to-left languages. E.g. some text may overlap with parts of the layout.

AdSense is not currently supported for blogs in Hebrew or Arabic.
Update, 2/25: AdSense widget is now enabled in Hebrew and Arabic.

iPhone Email HTML

Posting images to Mail2Blogger from an iPhone will not work if you include text in the email body below the image. The image will appear as a broken image on the blog.

Some labels are displaying an incorrect number of labeled posts.

Update, 1/15: Label counts will become incorrect if you delete a draft post with labels. Until we have fixed this issue, we recommend that you remove labels from draft posts and save before deleting the posts.

Update, 2/15: This was fixed in the 2/12 release of Blogger.