@marktheshark I'm looking at the same crossroads for my office system. I'm running a lower-powered Decware (rated at 6wpc) that sounds great with both sets of speakers I rotate through. My bookshelf speakers are rated at 85dB, but sound fantastic and I usually listen at 65-70dB with the occasional listening in the 75-80dB (max) range when my wife isn't home. I'm looking at experimenting with some more efficient bookshelf speakers, perhaps some Omega's, or moving to a 20-40 wpc tube amplifier. I do have a subwoofer and this is a smaller space measuring only 12x11, plus I only sit about 8' from the speakers.
So essentially I'm just wondering if there would be any improvement with a more powerful amplifier, or more efficient speakers, or both!