Blue Lagoon sans Hype

It depends on person. I was there and loved it and for me would be worth of the expense than wait 6 hours at the airport. By the way why did you put your question under Beyond Europe? Iceland is considered to be in Europe and is in the European Union.

Absolutely worth it. We had massages while floating in the water. Heavenly.

It isn't totally natural, but it's not a swimming pool either. The bottom varies in depth and the white is from silica mud. Google "the wonderful accident called blue lagoon" for a detailed explanation of how the Blue Lagoon came to be.

By the way why did you put your question under Beyond Europe? Iceland is considered to be in Europe and is in the European Union.
Because:
“In March 2015 Iceland's government requested that Iceland should not be regarded as a candidate country for EU membership".

Thanks for the two "thumbs up"; hopefully I'll get a couple more responses.

Yes, it's worth it. Buy the most basic, stripped down admission ticket you can without any frills, just basic access to the pool. (does it really cost $145 for two now??? wow!)

Also, you'll be glad that the water is hot no matter what the outside temps are...the power plant is not really a problem but it will stink of sulfur (and don't get your hair wet like I did, because the silica mud is tough to get out and it smells not-so-great)

It is absolutely worth it.

The water travels through the power plant because of its heat - the water has to be cooled down anyway before making it to the Blue Lagoon. The bus trip from the airport is direct and quick.

I was there 10 years ago so am not sure to what extent it's changed, if at all.

We went on a quiet morning before our flight back. Very neat, and yes, worth it.
And, yep, the communal shower/locker room thing Emma mentioned was in place back then, guess it still is.

It is not a big deal to be naked in showers in most European countries. Actually even here in the States in YMCA.

The Blue Lagoon is worth it for the experience. It sounds like it has gotten pricier since I was last in Iceland. If your other option is to just sit in the airport for 6 hours, I'd go to the Blue Lagoon.

For anyone with a longer stay in Iceland, I recommend the baths at Mývatn for anyone who wants to avoid the prices and crowds at the Blue Lagoon. Mývatn is cheaper, quieter, and much less touristy than then Blue Lagoon. The Blue Lagoon still has the edge in overall beauty, but I prefer Mývatn otherwise.

Regarding the power plant, as others have said, an Icelandic "power plant" is simply a geothermal hot water well. These are not power plants as we would think of them over here and are very clean. The only thing you'll see coming from these plants is water vapor and steam.

Okay, I've been watching this thread, and Jon, I'm glad you asked the question, because I've been curious about the Blue Lagoon, too.

This may be a really dumb question; but reading above not to get one's hair wet because it is hard to get the residue out of one's hair, what about bathing suits? Do they come clean (well enough by rinsing out to stick in a plastic bag for deeper cleaning several days later)? Or, is it best to take a really old swim suit and toss it?

Margaret, I followed the suggestion to put conditioner in my hair before getting in the blue lagoon and my hair was fine afterwards. They supply the conditioner.
http://www.bluelagoon.com/support/good-to-know/the-water-will-affect-your-hair/9/

Also, There was no issue with my swimsuit.