I recommend a shallow sand bed highly.
In my limited experience, it works great without any vacuuming. I have a herd of Nassarius snails that keep my sand bed clean.
When I moved all my livestock and live rocks from my 120 to 180 last summer, I left my sand bed in the 120 with just one inch of water above it for almost a month without any water movement. When I finally cleared the sand out from the 120, I found the sand bed to be fine and both my Alpheus pistol shrimp alive and well in it. The sand did not seem to be dirty for being in the tank for four and a half years without vacuuming. Additionally, I have a 7 years old shallow sand bed in my 15. No vacuuming here, either. Rocks and corals in this tank have been rearranged a few times, but I left the sand bed in tact every time. The tank has been very stable and things thrived in it despite all the disturbances that numerous re-aquascaping caused.