. . . . I recently added a trackpad to my MacPro. That now makes two mice and the trackpad connected to it. I am still using Snow Leopard.

I do CAD work. I have a Logitech VX Revolution mouse with scads of buttons, each programmed for a CAD function. Enormously useful (invaluable) for the CAD work, but nothing special as a general purpose mouse. I also have a Mac wired mouse that I never use and really ought to just unplug and put away.

After so much laptop time, the trackpad is the best way to go for some general functions, particularly web surfing, scrolling, changing apps, etc. I use Spaces and it is great for screen switching between my 10 active desktops.

I still prefer a mouse for writing and spreadsheets and any cut and paste stuff. Far more precise for me.

It eats batteries for lunch, however. Of course it would help if I remembered to turn it off when not in use.

Sanyo's Eneloop batteries would be a good choice, as you would be able to charge them as many as 1500 times.

You might try buying a set of four batteries along with a charger made for Eneloops.
With your mouse, you can check your battery level by clicking the bluetooth icon in the upper right corner of your screen. In the drop down menu you will be able to select Apple Magic Mouse and its battery level.

Once the level is low enough, I'll turn the mouse off, take out the old batteries and insert an already-recharged 2nd set. I'll then immediately charge the spent batteries and tuck them away in a drawer to be used again a few weeks later. I never turn my mouse off except to change out batteries.

The Ni-MH type batteries retain 75% of their charge capacity after as much as 3 years storage.

Please forgive me if you were already familiar with Ni-MH rechargeable batteries.

I bet I can use these for the keyboard as well. Although the keyboard doesn't eat them as quickly as the mouse.

My iMac, ordered with Magic Mouse and trackpad, also came with rechargeable batteries and a charger. I thought that was pretty cool.

I'll dig into my used batty bag and give it a try.

In the mean time I've ordered rechargables with a charger. Best of both worlds.

My daring wife would shit a brick. She hates change. She freaked when I added Lion. Lol Not worth the hassle.

I find myself gravitating back to the trackpad even I have the mouse connected.

I use it with my MacBook - open or in clamshell mode with a Bluetooth trackpad. I am not a "power user," so it has more than enough precision for me. I love the gestures. Managing multiple applications is a breeze.

I liked my Magic Trackpad under Snow Leopard, I love it under Lion.

The new gestures make it fantastic.

mouse for word processing and cut and paste.

But when I'm working on something that requires detailed control, I ditch it and go for a mouse. Not even the magic mouse, but a souped up PC mouse, that just happens to work A-OK on Mac OS X.

it's the best trackpad, period. the only PC version of a trackpad pales in comparison.

My birthday iMac came with both. I didn't think I'd use the trackpad much, but I'm really liking it. I have extensive hand/arm/shoulder problems, and the trackpad is often easier to use. Still mouse-dependent for Photoshop, iMovie, Audacity, etc.

I have an iMac and run SL and have the trackpad and the BT Mighty Mouse. 95% of my use involves the MM.
Just resistant to change, I guess.
+1 to Sanyo Eneloop rechargeable batteries. They power both my MM and the trackpad.