I used mine just last night on a batch of roasted tomatoes, onions and garlic. It makes a wonderful sauce for spaghetti or goulash etc. So quick and easy to use and cleanup is easypeasy as well.

Could also do a lovely carrot and parsnip puree, or any multitude of soups with it. It really is one of my favourite kitchen gadgets.

It's great for soups! Particularly butternut squash and the like. After cooking cubes of the squash in some broth, you can use the immersion blender to puree it, instead of having to put it in a blender. It's also nice when you want to thicken up a soup just a little.

definitely carrot ginger soup!

Tomato soup!!

I received an immersion blender for Christmas, so I've been asking these same questions. Mine has some cool attachments, so so far I've:

whipped up some egg whites
made a pesto with the chopper attachment
made butternut squash soup
made an individual smoothie without dirtying my whole blender

I'm excited to see what other people post here!

Awww... I wrote in with the exact same question but about a regular blender.. anyone care to chime in for suggestions for that as well?

Soups! for both immersion and upright blender

@AlisonCJ: I've made some batters for muffins and breads in my blender, I recommend putting wet ingredients in first, dry stuff can get all pasty and stuck to the bottom.

Have fun!

I use my Immersion Blender for soups (to puree a 1/3 of the mixture of a lentil soup, pureed vegetable soups) and for lattes! Heat the milk over the stove, whiz with the blender, and voila -- foam for a latte.

I christened my Christmas gift last night in some tomato soup. Mine also has a whisk and chopper attachment, and I've set my sights on making some hummus soon. I'd love more ideas!

I use mine mostly for pesto, soups, and tzatziki!

Make a creamy soup. Two easy ones are curry butternut squash and black bean. For butternut squash, saute an onion in olive oil, add 1 tablespoon or so or curry powder, salt, pepper, one package of pre-chopped butternut squash. Cook that a bit. Add chicken broth to cover (or more) and cook on low heat until the squash has softened. Now use your blender to make is creamy and smooth! For black bean, do the same, except add a teaspoon of cumin instead of curry and, obviously, black beans instead of squash (two cans, rinshed). Also add some tobasco to the bean soup and some fresh cilantro after it's pureed. Both soups are also good with a dollop of sour cream or yogurt.

i use ours on...well, quite a bit. ours has different attachments that make it incredibly versatile. the whip attachment is perfect for large batches of scrambled eggs as well as waffle and pancake batter, and i've been known to make whipped cream with it so i only have to dirty the container in which i intend to store/transport the end result.

I'd definitely do a "creamy" soup (with the immersion blender, it's so much easier to puree cooked veggies, so you don't have to add actual cream). The only caveat I'd mention is to make sure whatever pot or bowl you're using the blender in has high sides--otherwise, whatever you're blending tends to splatter.

I received an immersion blender for Christmas too. I've already used it for a couple of soups, which will probably be it's biggest use, at least during the colder months, but I'm curious to know how it handles smoothies. I've had my eye on a green smoothie recipe that calls for (among other things) fresh kale, spinach & frozen banana. I've been nervous to try it for fear of breaking my nice new kitchen toy. I know smoothies are a common use for immersion blenders, but do they handle these kinds of ingredients?

Mashed potato pancakes! Instead of mashing or whipping, mash and then use the blender. They're the perfect consistency the next day for smooth mashed potato pancakes!! :)

I used mine just the other night to make some wonderful potato and leek soup topped with white truffle oil! It worked wonderfully, much better than my food processor and it was significantly easier to clean up! I'm in love!

Smoothies too! A banana, some peanut butter, spinach, wheat germ, milk; whirl it up!
I've also made dips & hummus with it. So much easier that finangling w/ my crappy stand up blender

@AlisonCJ -- use it to make crepe batter. Alton Brown has a good recipe on the food network website. Just some eggs, milk, water, and flour, blend it up, stick it in the fridge for at least an hour and up to a day or so, and voila -- crepe batter! Also, I often use the upright blender for hummus or soup instead of the food processor because it makes a smoother, creamier consistency (you don't want that for everything, though, so use your own judgment / taste as a guide).

Definitely a banana in ice-cold milk! Yum!

Immersion blenders work great for Hollandaise sauce... or many emulsions for that matter. Rich and fluffy every time.

Tumbleweed

@onebravegirl - mine does well with smoothies as long as I make sure not to put TOO much frozen stuff in. Make sure you have enough liquid.

if you find a glass (we use a cocktail shaker) that fits the blender stick well you can make quick and easy hummus out of different canned beans and flavorings.

I use it for many of the above purposes, but I don't think this one was mentioned:

protein shakes, as in from powder form. I add a few cubes of ice, the powder and either milk or water and it really mixes it well. my protein mix of choice is shakeology, makes me feel quite healthy and easy in a pinch.

I have used mine for both whipped cream (extremely fast!) and for making mayonnaise, when I had a lot of eggs to use up. I know that there is a whisk attachment for my blender, but the standard attachment worked just fine.
It works great for making things like salsa and salad dressing, too.
(I have read that immersion blenders aren't fond of ice cubes, so I would be careful using it for smoothies using those. It does, however, work great for green smoothies/smoothies using oats as a thickener.)

I have an attachment that is like a contained bowl and blades and I use my Bamix with that to chop nuts, herbs, seeds, bread.. it's handy!

Definitely home-made mayo, but only with 1 egg, not more!

For things like hummus, fresh tomato sauce for pizzas and well most anything we went to the store and purchased a couple of those plastic jugs some taverns serve draft beer in (but smaller). They cost about a buck and when they get looking scratched or stained (tomatoes are like that) just buy a couple new ones.
The size is perfect and you won't have to deal with splats of food on kitchen walls and such.

There are already so many good ideas here! I love my immersion blender and I'll never go back to a regular blender. I recently used it to make cream of spinach soup. It's also great for making Moosewood house dressing. Enjoy your new toy!

Potato leek soup! Or garlic aioli to go with grilled artichokes! Yum!

I make green eggs for my kids (and myself) which is basically 4-6 eggs, a cup of frozen spinach and some cheese. Puree it all together and cook, as you would scrambled eggs. The spinach is basically liquified so you can't pick it out, and the eggs are delicious.
Got the immersion blender to make babyfood and I've used it for so much more than that.

Just got an immersion blender...I've never seen my boyfriend so excited to do anything in the kitchen since I showed him my little wheelie garlic chopper. Pureed tropical fruit to stuff in a pork chop, then made guacamole...next morning I pureed some fruit with a little OJ I had to make a Bolthouse style fruit drink and also whipped up some cream to top an apple crisp. I'm pretty much looking for things to puree now.