Wow, where to start...
"quality equipment" can be $1500 or $7500 depending on your budget. The basics needed are camcorder, housing, lights and editing hardware and software.
My current recommendation is to seriously consider an HDV setup. Everything is going HD over the next couple of years - broadcast television, cable, DVD players etc. so to do less seems to be buying into obsolescence.
Sony's just released two single chip CMOS HDV cameras - the HDR-HC5 and HDR-HC7. Either one will work for a prosumer setup that will allow you to produce "awesome" videos. There are also new HDD and DVD based models from Sony, Canon, JVC and others to consider. The hard drive models have the ability to store more information than a tape model, but the trade-off is that they're using a new format - AVCHD and current editing software doesn't yet support it. Also they write to the disk at a lesser quality than HDV does to tape.
Another option is to purchase any of the MiniDV format cameras that are still available if you're looking to save money. These can be had for as little as $3-400 but the image quality won't be as good. There are some higher end 3CCD MiniDV cameras but at their prices HDV becomes an alternative as it produces superior image quality.
If money's not an option, one of the 3chip models could be considered. Sony's new FX7, the slightly older FX1 or models from Canon are available starting somewhere in the $3000 range. Most have a lot of added features. Housings will be proportionally more expensive for them also. Check camcorderinfo.com for reviews of most recent camcorder models.
Housings are divided into two types, mechanical and electronic. Both have their pros/cons. Reasonable mechanical housing mfrs. are Ikelite and Equinox with Gates being the high-end. Reasonable electronic housings can be obtained from TopDawg or Ocean Images. More expensive electronic models are from USVH, Light&Motion and Amphibico. Links to all the housing mfr's are
here.
Pricing for housings starts around $800 and exceeds $6000 with all the toys included. I think you'll find that more manufacturers support Sony camcorders than any others. This is because Sony still provides a LANC control port on most of their line. This is the way most of the camcorder functions are controlled in an electronic housing.
Then there's lights. Which are useful not only in low-light or night conditions but also can be used in daylight to improve the visible color spectrum. I'll let someone else post light options since I don't use them.
Finally you need enough computer to edit your videos. For MiniDV this can be just about any recent desktop/laptop computer. Using either Firewire or USB 2.0 for transfer. Firewire also allows you to control the camera during editing.
For HDV editing on a PC, there are some serious hardware requirements, most packages require processors in excess of 3GHZ, several GB's of ram and fast big hard drives for capture. I'm currently building an HDV editing system consisting of a fast dual-core processor, 2-4 GB's of Ram and at least 640GB's of diskspace. For software I'll be using Sony's Vegas. Adobe's Premiere and others are also options.
For Macs, imovie works initially but more serious work seems to be done with Final Cut Pro. Not being a Mac user I can't recommend anything.
These are my suggestions, Admittedly I have some biases based on my experiences so I hope others will post their recommendations also.
