HDR Tonemapped images seem to divide opinion much more than anything else... colour vs black & white, digital vs film. It tends to be something you either love or hate.
I believe that it's not so much the technique that is liked or loathed, but rather how it is implemented. Just because someone buys a top of the range camera, doesn't automatically mean they can take better photos than a camera from the bargain basement in the right hands. No matter what the equipment, subject or techniques, there are good and bad examples of how they are used or misused.
Not a Magic Fix
HDR will not fix a bad composition, poorly focused, uninteresting subject. No amount of Photoshopping can make a fundamentally flawed photo look great. Carefully executed, HDR can make it look better, but no truly awesome photos start life as something mediocre.
Just like any other technique, such as sharpening or colour correction, HDR can be poorly implemented. But conversely, when executed properly, I believe it can produce truly stunning results, the kind of output that has never been possible, until recently.
Re-defines the Rules
The HDR technique breaks through the barriers of existing camera technology, by allowing the photographer to regain the detail lost in the shadows or highlights. E.g. when inside on a sunny day, look out the window. Now take a single photo. It will be just about impossible to get that photo to look like what you're seeing... unless you combine multiple exposures. HDR makes it incredibly easy to create a photo where the interior and exterior are both correctly exposed.
Moderation is the Answer
But it's cheating... say the purists. Some people prefer the traditional photo look, with dark shadows and blown highlights. These are fine, if that's your intention. But what if you want to create a photo which looks more like the scene as you remember it?
My rule of thumb is to try and re-create the scene how I remember it, which means bringing back detail to the underexposed and overexposed areas, while trying to remain true to the overall exposure and colours. Sometimes I will blend back in parts of certain exposures, where the HDR technique fails. This happens at times on skies. HDR purists may turn their noses up at the very thought of this, but I'm not consciously trying to create an "overcooked HDR look" here.
I use Photomatix to generate HDR. So far it has given me the best results of any software I have tried, combined with ease of use. The interface isn't great, and mishandled it can produce some truly horrific results, but with some practice, I have yet to find a better/easier program. Tip of the day - keep the Light Smoothing on "Very High" and the Saturation no higher than 60, Micro-smoothing around 12, and Microcontrast around 5.
It Doesn't Fix Everything
Just as important, is to adjust the curves to create accurate contrast and colour balance. Some technical aspects also need to be taken care of, such as minimising noise while retaining detail, and correcting flaws, such as chromatic abberations. I will also regain the detail in shadows and highlights, always aware of not overdoing it. Just because you can bring back all the detail in a shadow area doesn't necessarily mean it's the right thing to do. At times, I will let the shadows or highlights max out.
Finally, I use a "Lab Colour" trick to add some punch to the colours - while bearing in mind once again, less is more - it's easy and tempting to overdo it. I'm not afraid to de-saturate the colours at times. Last of all, I'll do some sharpening which often really brings the whole shot to life.
OK, so I've gone a bit further than the HDR good vs evil debate. Overall, HDR is not to be feared... once it is understood and used carefully. While I have developed my own workflow for HDR photos, it is evolving, as I experiment and look for new techniques to improve my work.