If you opt for the wide-angle lens on the DC600 (and if you dont you are not taking advantage of this cameras true potential), then spring for the dock. Keeps the wide-angle handy without being in the way. No fumbling through pockets, no worrying about dragging it along the ocean floor. One complaint - after 4 days of diving the mounting screws started to come loose. You may want to lock-tite them or at least keep a small screwdriver in your dive bag.
While I give the camera itself somewhat mixed reviews, the wide-angle lens is AMAZING! Pops out of the holder and onto the camera in seconds, even underwater (so no topside decisions on which lens to go with). Funny thing is I ended up taking almost all of my shots with the wide-angle in place. Allows you to capture more of the subjects surroundings (coral, sponges, etc) as well as large subjects without being out of the cameras optimal focal point (I captured a 110-ft wreck almost in its entirety from <10 ft off the port-side bow). You will definitely want to add the lens holder that attaches to the bottom of the strobe base.
Its a free bag with purchase... what do you expect? It is roomy and durable and can handle both sets (mine and my wifes) of warm-water gear, including my 31" long fins. On the downside, 2 sets of warm-water gear gets heavy to lug around after a few days. If you want a storage bag for your gear during the off-season, this one will work fine. If your going to be hiking it to the dive boat every morning, might I recommend something with wheels?
Let me begin this review by saying that if you are looking for a good TOPSIDE camera, this is not it. While it takes reasonable quality pictures in full light, the DC600 performs poorly in low-light situations. The 7 different exposure settings for use topside seemed only to hinder the cameras performance, as the shutter speed is already too long in Standard mode for most light conditions. The longer exposures (basically everything but the normal mode) left the aperature open far too long and even my tripod couldnt completely remove the blur. The high-speed mode provides you with blurry, overexposed photos... not action shots. I was EXTREMELY unhappy with this purchase... UNTIL I TOOK IT UNDERWATER! Underwater this camera performs very well. The strobe was more than enough without being overbearing and the white balance in the sea mode is ideal. One caveat was the short focal length - anything beyond 2-3 feet of your subject led to fairly dark pictures, but in all fairness the water we dove was fairly sedimentary. However, up close and with the wide angle lens (optional but a MUST HAVE) I was able to capture some truly magazine-quality photos that printed to 8X10 with excellent color and sharpness. Bring a different camera for topside photos indoors, at night, and action shots. Everything else the Sealife DC600 can accomodate.