The way I have things set up with my Razer naga is this
I have the keybinds for the L-Trigger and R-Trigger set to numbers 4 and 6 on my mouse. I then set the cross-bar type to toggle, so that once I have hit 4 or 6 to open up either side of the cross-bar, it stays open until I close it.
I then have mapped the up, down, left and right D-Pad buttons to 1,2,3, and 5 on the naga, and use them to cast those corresponsing spells.
I can't seem to get the Cross, Circle, Square and Circle buttons to work with this so that means I have eight abilities I can map to the keys on the mouse, and then I just toggle between button 4 and 6 when I need to swap to open up the other four abilities.
I am not sure how this would work without a naga, depending on what you are using you may have to map everything to different keys to get it to work for your setup, but I am finding this works perfect if you are using a naga, flows very smoothly.
I like healing and it works out because I can toggle open a side and I then have mouseover macros made for things like Cure and can just mouseover peoples' nameplace and hit the corresponding key to make healing super easy!
Hope this helped a little ... to those who were talking about mapping things to the keyboard. --- We live on front porches and swing life away. We get by just fine here on minimum wage. - Rise Against