I used to love this plugin and I'm quite sad that it is not available in Lion. While, yes, the new default view provides a 3 column layout the default view also sucks. Mainly because it is not possible to mark the unread messages (and only the unread ones) in bold.

To do that you have to switch back to the classic view with the old layout. But without letterbox this classic view sucks too. So now I can choose between not being able to properly see which of my messages are unread or using an ugly layout. Not sure which of these is the lesser evil.

I hope they fix this.