It took me a while to get accustomed to work with custom settings on the Nikon D200. I actually, didn't touch this option for almost year. What a mistake! Using custom settings, I can easily change a whole lot of setting for colour balance, image quality, autofocus etc by the changing to a different preset. If I want to do candid shots at a family gathering, I select my point and shoot setting with a bit more intense colour, using the built in flash for TTL exposure... If I want to take a serious portrait of a family member, I change to the custom setting for portraits with raw compression and activated CLS for more interested lighting with my SB 800s. The nice thing is that you can define up to 4 different custom setting setups.
To begin with, there are two custom setting menus, the first you find in the Shooting Menu, where you define on how to optimize the image, image quality, compression, ISO settings. In the Custom Settings Menu, you can set option for autofocus, metering, timeers, shooting display etc. Which means, you have to work with two different setups and need to change both, which still is much faster than changing the settings manually.
I found a nice version at Nikonians' webpage. They seem to have some server problems at the moment. Check them out later today or tomorrow. I hope they will be up and running again by then. Search their webpage for "Custom Settings v1-5". It is an Excel Spreadsheet, which offers you a great starting point.
I downloaded the spreadsheet a couple of weeks ago. I copied each and every setting in the two custom settings menus. Then, the fun started and I explored what works for me and what doesn't. Some settings are simply great and work fantastic for me and other simply are not, what I am after. The real nice thing about custom settings, is how is easy they are to setup and change.
You simply select the custom settings bank, you want to work with. Go into each and every menu and submenu and enter the changes you need. Not happy? Just change them again.
Be aware the next time you take pictures, which custom setting bank, you chose. You don't want to take your high profile portrait with your point and shoot settings! It takes a bit to get used to, but for me it is second nature. After each photo session, I set my camera back to my favourite custom setting bank.
Have a look at it and play around. It is a feature worth checking out further.