I recently picked up a copy of Hero & Heroine by the Strawbs. It isn't acoustic, but the reviews on Amazon had it picked as their best effort. I also picked up Heresy by Univers Zero. I had to order it off Amazon because I couldn't find it locally.
The Univers Zero stuff is really strange. I have listened to it twice, but I am compelled to hear it again. Very interesting.
On the other side, I have also listened to the Strawbs twice; however, I am not moved by them as much.
The Rock In Opposition, RIO, are very intriguing. I need to hear some more.