I'm always raving about the geysers in Yellowstone, and for good reason. There literally is no other pace on Earth like Yellowstone. However, that doesn't mean that there aren't amazing geysers in other parts of the world. Heather saw some in Iceland where the original Geysir is. In fact, the name "Geysir" has been copyrighted so no other geyser can have that name. Iceland's geysers used to be much more impressive in general, but the geothermal energy has been tapped and the geysers have been largely destroyed. Still, Iceland has some impressive geysers and I'm looking forward to seeing what Heather has to say about them.
New Zealand has the same problem. The North Island used to have the second-largest geyser field in the world (at least 300) until it was developed. It now only has about 40 geysers. The geysers in Kamchatka in Russia have fared better since that area is so remote, but there have still been proposals for development there.
Kamchatka has only recently been discovered to have hundreds of geysers- still not on the scale of Yellowstone, but enough to make it the second-largest geyser area in the world. Unfortunately (but fortunately too), the area is very remote and it's difficult to get there. The largest geyser area there has been protected in a park much like Yellowstone, but because you can only get there by helicopter, tourist dollars aren't coming in to help support the Kronotsky National Biosphere Preserve.
There are also geysers in a lot of other places around the world. The Rift Valley in Africa has a few (I have always been fascinated by the Rift Valley even before I knew it had geysers), along with El Tatio Chile. In fact, Chile is third only to Yellowstone and Kamchatka in the number of geysers it has. El Tatio is easier to get to than the Kronotsky Preserve, but still, it is fairly remote and it's difficult to spend many days there.
Tibet is the place I'm interested in now. There are definitely geysers there, but the question is how many and how powerful they are. Very little research has been done there and rumors of Yellowstone-like geysers fields are very tempting. But Daoud's not sure he wants to strike out into Tibet looking for geysers with me. I can't imagine why. :)
So, if you ever go to Yellowstone (again), remember what an amazing place it is. Make sure to take the time to really see the geysers- you'll probably never see them anywhere else.