DeeG,
You mention a host of applications you would like to use the 12v for but I'm not so sure it would be a good idea. Many of the recharges you mention may very well be of application specific design and connecting a universal 12v supply to to your cell phone or gps may just void the warranty in a spectacular way. For running a 12v air pump or  firing up your Gerbings an outdoor light transformer [think Malibu lights] may be a good accessory. I Also like the overhead auto retracting cord reel. I'm remodeling the shop as well, some pegboard and also track lights from the recently remodeled kitchen are going up. Also looking for a small but good quality tunes box.
rich

The 12V requirements/uses will have to be well defined before any kind of recommendation could be made...

Just wire your garage to code with a few seperate 120v circuits and buy yourself a standard bench top 12 volt dc power supply many of which come with a built in car cigarette lighter jack on the front and you could use your car style chargers plugged into that...like this  :

http://www.autotoys.com/x/product.php?productid=7208

After the electrical/radio genius at work overheard me chatting about wiring up the shop, he offered to come and help. Well, he offered to come over and teach me how to do it.  This guy wires up all our radio towers and everything associated with our comm center, and he built the two houses he has on his property, so I think I'm in good hands.  Which is probably just as well, as the spouse is thinking that maybe we should install a couple of them radiant heaters so we can work in the winter and not freeze to death.  

He also pointed out a 12V converter box thingie he had on his workbench.  About $100.  The one that ampliflyer posted the link to would work just as well.....

MrRiden,  I've been wanting a radio/CD player for the shop as well.  I have a set of Altec Lansing computer type speakers set up in my kitchen. Fairly inexpensive (about $90) and it sounds really nice.  I'm going to use a Am/FM/CD player that I already have and just plug it into the speakers.  It also has a port for an MP3/sat radio as well.
The one in my kitchen is plugged into the Garmin GPS which has the XM puck on it.  

Now I just have to wait for the temps to cool a bit before I start the project.  The shop temp was about 8 degrees warmer than the surface of the sun this afternoon. I had to wait until 10pm before it was tolerable to work in.