Just had to add my 2 cents worth on Iceland...if you can afford to go, do it!
I had the amazingly good fortune to not only visit Iceland back in 2004, but to actually develop and teach a physical geology course at the college on the NATO military base that summer (which I made field-intensive, for obvious reasons).
The country has everything a physical geologist could ask for--numerous active volcanoes, landscape dominated with volcanic features, geothermal features, RIFT zone, glaciers and glacial features, amazing waterfalls & rivers, canyons, hot springs, etc.
Perhaps my favorite memory was taking my students into the rift zone itself where we sat to eat our sack lunches--not many can claim they ate lunch IN a rift zone! (To add to the memory: a family of ducks obliviously waddling by while we were eating.)
Besides taking students to a volcano, a glacier, the rift zone, and a geothermal area, I also took some side trips on my own, including a Hummer jeep tour up the side of Grimsvotn where my adventurous guide proceeded to drive up the volcano, according to him, higher than any other guide had ever taken his group, in order to accommodate my request to retrieve ash samples. (This tour included my 15-yr. old nephew who thought this was great; but also a 50-ish age couple who was terrified.) Drove through raging mountain streams with water up above the bottom of the door where I thought the guide might have gotten too adventurous but always got us through, hiked up volcanoes & glaciers, experienced the Blue Lagoon as well as a "clothing optional" less urban hot springs--even met some of those daring (and yes, handsome, Lin!) strapping blonde young local gentlemen.
Flew across to the Westmann Islands to experience even more active volcanoes and the abundant bird life there, including huge colonies of puffins, and even flew over to Greenland and collected the most amazing metamorphic rocks as well as visiting a native Inuit village and learning something of their culture.
Truly an adventure, and an experience, of a lifetime.