It depends... In some situations, I've seen photographers "chimping" so much that they were actually missing a lot of the action. But it's essential in other situations, to check that you "got the shot". A wedding is a good example, but even then I'd say it depends upon whether one is shooting candid shots in a fast-moving situation you can't control, where chimping probably costs more shots than it saves... versus shooting planned and posed shots that you MUST get correct and should chimp to check frequently.

I deliberately set my cameras to NOT playback every shot. I don't want the distraction or to be tempted to chimp a lot. (It also saves a lot of battery power, preventing each and every image from displaying on the LCD, which is a power hog.)

I do have my cameras set up so that I can recall any particular image quickly and easily with either right or left thumb. Most of the time that's to inspect the histogram, sometimes to confirm composition or to magnify the image to inspect focus accuracy. I DO NOT use the image replay for other close inspection of the image, because the image isn't calibrated and the LCD screen is highly influenced by ambient light conditions. That's why the histogram is much more informative about exposure and color balance, contrast etc. can't really be judged from the image playback. It's really only useful to check composition and, in a more limited way, focus accuracy. When shooting with any of the auto exposure modes, I also use the info that accompanies the image playback to review shutter speed, aperture, etc., watching for any wildly incorrect settings (which sometimes occur when the camera gets bumped) and making fine adjustments "on the fly". And, for certain shooting situations I make regular notes of the camera time, for quicker reference later when I'm sorting and editing several thousand images in post-processing.

Correct! viewfinder gives you focus confirmation, ISO (if using AutoISO), shutter speed, aperture, and if you use spot meter mode, you can read the highlights and place the exposure needle where it needs to be to either avoid blown highlights, or you can make a decision about how much blown highlight you are willing to compromise on. If you use the spot meter to measure the entire scene you can accurately determine the contrast range of the shot, and whether it will be helped by shooting it as an HDR stack. My exposures are generally pretty good, and with the natural subjects I shoot, I check the LCD more to confirm there was no subject (or photographer) movement and that the eye is perfectly focused, that to judge exposure.

I started serious photography in 1973 with a 35mm film camera; I've been shooting digital for the past 6 or 7 years. I "chimp" all the time I don't care what anyone thinks about it. I like looking at the shot I just took. Sometimes "chimping" is beneficial. Last year I was shooting in Utah and forgot to change my camera setting from shooting a sunrise to shooting in the middle of the day (something else we're told not to do -- but what happens when you're in the middle of nowhere, going somewhere that's too far away for you to get back at either of the golden hours?)--I digress. I forgot to change my settings and immediately noticed that my photos were way, way overexposed. I only knew that because I "chimp." Now, I think I'll eat a banana!