i bought both the intova ic800 and is2000 strobe.
i have since moved on to a panasonic zs3 (still have the strobe) but some of my funnest and most challenging photos were with the ic800.
first of all the ic800 is a slow shooter and has a slow recycle time- so this means that your shots have to count. secondly, it is prone to blurriness, so you have to control your bouyancy and keep as still as possible especially for macro shots. i would usually hold my breath for a short while (if there isnt a current) or slowly exhale to keep me as steady as possible.
however things get much easier with the ic800 when using a strobe. first set the camera to iso100 (best quality shots) and a shutter speed of 1/125 (effectively stops the action) or just keep it in sports mode. next just angle your strobe so that you dont get a washed out subject and you also avoid a little backscatter.
although i never had the wide angle lens, im not sure if it would help. i dont know if you noticed, but the ic800 cannot focus closer than 4 inches or so. so even if you had a wide or macro lens, you still would be limited by the cameras optics.
those tips helped me a lot and this camera improved my bouyancy and awareness tremendously. so even if i did not get the best pictures with it, i do have some very fond memories with my time with the intova ic800.