Earlier this month, I showed how the corrected (finally!) vertical line spacing issue had been corrected, and how easily you can tweak the line spacing for elements like pre-formatted blocks. At that time, vertical line spacing for pre-formatted blocks was predictable, and could be tweaked. Since that time and just before the (mostly Draft) New Blogger June 2008 release, vertical line spacing changed.
You can see the problem, in Blogger Spacing Issue Fixed - June 2008. When I wrote that post, the code displayed, as I describe farther down in the post as
tighter vertical spacing (1.2em)
Now, it's not tighter.
Coming just before the release of New Blogger June 2008, we have to wonder.
>> (Update 6/28 21:00): This issue appears to be fixed.