Thanks fellas... 
Jan - Yup! I'm using the Inon UWL100 Achromat Type 2 + Dome Unit, that screw directly onto the housing port (no adapter needed). 
Loftus - Now, that's really good question. Hmm... This is going to be long... 
Basically, both are really good cameras, each have their pros and cons. I have a very strong passion for diving, especially UWP. I enjoy shooting the small critters and the colorful reefs. In short, I want a camera that can give me both... 
The G10 has a default of 28mm, but UW it becomes 30+mm and since I'm using the OEM housing, I can't attached any WA lenses so I ended modifying the dome unit to fit the OEM housing (for my Fak-fak trip). I was pretty unhappy with my Canon during my Maldives trip, last year. Imaging shooting Mantas & Whale Sharks with a 30+mm camera (UW), total frustration. No doubt, the Canon G series has fantastic macro capability, but when it comes to WA, nothing to shout about. Even with a third party housing, changing of port is required (to a shorter port, limiting the zoom function). Basically, to gain certain thing, I have to sacrifice the other.
The LX3 really fulfilled my needs, I can shoot macros and WA with the same camera. The LX3 has a default of 24mm and with the Inon UWL100 + Dome Unit, I'm getting around 18-20mm and that's probably the widest you can get from a compact camera now, wished I had it during both my Maldives & Fak-fak trip. 
However, the macro capability of LX3, can't compare to the G10. At the same time, I feel that the market will be going for a wider and wider lens (looking at the the trend now). When the lens get wider, I foresee the zoom function being reduced (just like the G9 to G10).
The thing I like about the G10 is the macro capability and faster focusing. However, I believe Lumix(Panasonic) has the R&D and technology in improving their products. Moreover, they are using Leica lenses (everyone knows the quality). I realized is that images from G10 tend to be sharper than the LX3 on the cameras LCD, but when uploaded onto a computer, images from LX3 are sharper. Like I said earlier, Gain some, Loose some! 
That's the reason I switched and anyway, I've always like the challenge of trying out something new. Just like diving, it feels great to be the first few to explore a new site and then tell others about it. Hehe... 
I strongly believe, Lumix is going be a force to be reckon with, in the near future. Just check out their technology: http://www.dpreview.com/news/0903/09030316...xgh1handson.asp
Ed.
*Anyway, it's just my personal opinion. I think both cameras are fantastic, just that I find the Lumix LX3 fits me more. 