The G9 is a good choice, tho' I think any accessories for it should also fit the G10.

I use two different u/w compact cameras, each in the manufacturer's housing - a Canon S500 and a Casio EX-Z55. Both from the 5mp era and way inferior to your forthcoming G9, but still capable of good results if you stay inside the design limitations (if you try to do things the camera isn't designed for you end up with rubbish). I'd like to get a G9/10 but finances are a bit tight right now..... I also want to get a Canon 16-35 lens for my 5D at c.$1600, a Canon 24-70 lens at similar price, plus a couple of flash guns at several hundred $ each, but they will also have to wait. Oh, and a carbon fiber tripod, and ..... The list goes on!

If in due course you do get a DSLR you'll find that the real cost isn't in the camera itself but in the lenses. Especially with a camera like the 5D, which shows the slightest flaw in a lens. I've already spent several thousand $ on lenses, and I only have three! Shows how important it is to choose the manufacturer and sensor size before you start buying lenses - jumping ship gets costly.