Since I have the 12MP 450D (still going strong) I wouldn't lose resolution when shooting the G1-X at 3:2 aspect ratio (which is my preferred format anyway).
I think many would have preferred a native 3:2 sensor to match their DSLR, but you don't loose too much if you shoot in this format.
4:3 14.2 mp
3:2 12.6 mp
16:9 9.8 mp
Slowly learning to use the 450D, the Canon G6 and the Fuji F200.
Public pictures at http://debra.zenfolio.com/ .