Hi!
We had a discussion in shoutbox about how to handle WOW with the use of only one hand.
In game I've tried to help somebody who also has the use of only one hand and a couple of people have lost digits so it isn't a very uncommon problem.
That's just a challenge and you will have to make your one controller count.
Things are easier if your useful hand is the right one since there are some frankly awesome mice for just that.
I will try to keep this thread updated as suggestions roll in.
Now what I need is more ideas. for instance I heard of folk using trackballs. There is that Logitech G13 and a couple of great mice I don't know.
Mice Logitech MX Revolution
This mouse has a very precise resetting scrollwheel for thumb usage. You can set this to strafing. It also acts as a button which you could set to forard/backward movement. The two buttons above that are very reachable and should also be customized.
This allows for movement while clicking on skills in the interface.
To my knowledge there is no direct lefthanded version of this mouse but Logitech has a couple of very sophisticated left handed mice.
Razer Naga
This is a new mouse that promises quite a bit of potential to replace the keyboard alltogether. I have yet to see it in the wild so I can only say that if all those buttons turn out to be reliably reachable by the thumb this could very well be my next mouse.
It has sparked some conversation here on TS.
New Razer MMO Mouse
Key Pads Belkin n52te

Now what I use is this little baby here. It is as good as it looks. You don't have to move your wrist, just your fingers. It is very ergonomic. The direction keys for the thumb are not as precise as I wished them to be and I seriously doubt it is practicable to bind them to the mouse cursor. There is no version for the right hand to my knowledge.
Pedals
Now I haven't used pedals since I stopped playing hardcore combat flight sims, but those ad another tool to your arsenal. It does take some time getting used to.
Synapse fessed up shielding by foot so it most definitely is an option.
Fragpedal Elite USB Gaming Footpedal 
A quick Google yielded this baby. I don't know it. Looks nice.
Weapon User Interface
The user interface is the most important thing to customize and yet I will have to work in it. Since I want to try everything that I suggest myself it will take time.
Meanwhile I can just explain what I had used in the past.
Group Buttons 
Back in the day when I still was a clicker I used a great add on called Group Buttons. It allows you to put buttons underneath portraits applying those skills to the target belonging to the portrait.
Group Buttons v4.98 - Interface Additions - World of Warcraft Mods, Addons, and More!
Loz had made a very nice UI addition which brightened my day as a clicking healer in 5 mans.
It hasn't been updated since 2007 but there are alternatives which I will look up for you.