Great for making smoothies (I always have some frozen bananas and other fruit in the freezer), but it doesn't chop ice or large chunks very well. Although, it's easier to store and have available than a blender. Works great for soups and purees. Make your homemade vinaigrette a true emulsion. I guess you could also make your own mayo, but I never had the desire.
I found out about this immersion blender from a vegan friend of mine who uses it for making hummus on the spot whenever company drops it. I've made hummus many times, and since haven't used the store-bought stuff.
This is not good for making salsa, as it tends to liquefy the ingredients in short order.
This is the Cuisinart CSB-77, which also comes with a chopper/grinder attachment that looks like a mini food processor, and it comes with a whisk attachment. Both of these are really more trouble than they're worth, and you're better off using a knife and a hand whisk.
Still, this is one of those tools I use nearly everyday for over a year now. And this is the second one I have. The first plastic beaker developed stress cracks and the markings rubbed off. Cuinsinart replaced the whole set since they couldn't have the beaker separately in stock, and it was still under the 3-year warranty.