I haVe to say unsharp mask. It looks incredible to set its threshold to 0, and put square size between 9-17. Simply awsome. (btw, I'm not sure if Photoshop has it with that name, cause I use arcsoft photostudio).

Cloning stamp. Almost any photo can be subtly enhanced with this versatile tool.

Wacom pen tablet.

history brush, apply an effect to the entire pic, fade it to 0, then use the history brush to slowly brush the effect into just one part of the image.

The Healing Brush in Photoshop, it lets you touch-up almost anything, and with near perfect results. Crop and Free Transform are some of my other favorites. For the best all-round feature, I'd have to say Curves.

i'm begining to love curves aswell, using them as an adjustment layer with a mask, or possibly two different curves applied to different parts of the pictures. crop is also really handy, and i love the new 'shadow highlight' feature for saving bad pictures in shadows. i've never figgured out the healing brush, you should show a little tutorial on how it works Will :P

the healing brush is similar to the clone tool. I use them both, mostly healing. the difference is the healing brush works sort of like a blemish removal tool in other programs, using a function to combine the sampled pixels with the ones already there, and the ones sorrounding the area you are working with. The result is quite nice. Also the healing brush returns to the same original sample point everytime u let go of the mouse button, unlike the cloning tool which moves with the mouse whether or not you are pressing the mouse button.

ahh thanks for that, i'll pull it up sometime that i have a job for it, sounds like it saves some preciseness and time required by the cloner