I have been playing with HDR photography recently and found these settings to use in Photomatix. One problem is trying to stop the end product looking like a cartoon. I prefer Dynamic-Photo HDR as the photos look more nature and this is a better program for aligning hand held photos however the trail version puts a large watermark at the bottom of each saved photo.
I setup my Canon 300D on a tripod (if possible), then use AV mode set to f11. I set the Exposure Bias to +- 2, then I use the cameras self timer function to minimise camera shake.
Photomatix settings.
Strength- 100
Color Saturation- 89
Light Smoothing- Highest (I always am at the highest, or second highest mark)
Luminosity- 5
Under the tone tab
White Point- 1.568
Black Point-.669
Gamma- 1.00
Under the color tab
Temperature- 3
Saturation Highlights- 10
Saturation Shadows- 10
Under the micro tab
Microcontrast- -2
Micro-smoothing- 3
Under the S/H tab
Highlights smoothing- 18
Shadows smoothing- 24
Shadows clipping- 11