The Oxygenics showerhead is definitely worthy of inclusion here. With a nifty design, the showerhead is able to take low pressure water and transform it into a forceful stream for showering. It does this while using just 1.5 gpm (gallons per minute). It adapts to variable water pressure, and any water pressure from less than 20 psi to 100 psi.
Internal mechanisms also enrich the shower water with oxygen. It also comes in a 2 gpm hand-held design. The hand-held version sells for about $45, the showerhead version sells for $30-60.
Available from: Amazon ($29.97)