Be or not to be FX ...

1) The DX / FX debate is a pure technicality.

I think you are completely right with this point.

This is based on the assumption that better gear will get you better images. I am at a point with my photography where I know I have still lots to learn and the thing that is going to improve my photos, if anything, is me, not technology. This will stay like this for a long time.

This is probably true for the majority of us... We just have to remember great images that were shoot in the early years of u/w photography. Those great images stay, technology go away...

3) What is wrong with my current gear? Nothing! It takes awesome pictures and I'm happy with the results.

I raised this question to get the comment of all about this.

I'm actually using a D70s and thinking of renewing for better quality at higher ISO since I dive mostly in dark water. Basically I can : 1- go with a D300 and keep my lens; 2- go for FX with for let's say a D700 and buy all new lenses; 3- wait for and eventual new model...

If a D400 comes out, you can be guaranteed it won't fit in a D300 housing.

I am wondering why not more discussion on D90 vs D300 for underwater usage. I am giving up D300 and go for D90 because of smaller size and lighter weight with basically everything I need that a D300 offer. What would be something D300 offer that a D90 doesn't have and relevant to underwater usage ? I will wait for the D300 or D700 replacement for top side when it happen, meanwhile, I think D90 would be just fine, isn't it ?

"If a D400 comes out, you can be guaranteed it won't fit in a D300 housing."

I would be too sure. They only thing that is different between the former D200 and the D300 (on the outside) is the LCD panel was enlarged on the D300. What I have been hearing the D400, it will be housed in the same body, the upgrades are all internal.

Canon's 40D and 50D are prime examples of this.