I have a mighty mouse that came with my G5 and i like it. For the Powerbook i have a microsoft bluetooth mouse and it is also very good.

slight O/T [rant] "Why is it so difficult to buy a decent mouse now that has a cable I don't want wireless my mouse stays on its mouse mat which is 8inches square why the hell do i need wireless for that, Now don't start me on wireless keyboard for desktops {/rant]

As to keyboard i would not go beyond the apple keyboard i have one for my G5 and a bluetooth one for the powermac.

As to running photoshop it will be fine, it won't be the snappiest thing on the block but i think to general working you won't have any problems.