Waste of money:
Very expensive wok. Turns out, it's easier to buy chinese food.
Panini press. Forgot I had it and I don't like paninis. I can crush my own bread just fine.
George Foreman grill. Easier to go to the BBQ or get out a frying pan.
Breadmaker. Mine was a vertical and it was so tall, I couldn't put it on the countertop, so I needed a table for it which got in the way. And we didn't like how the bread was like a stone on the one end (bottom) and not very dense on the top, so I started just using it to mix and proof my breads, then made buns in the oven. Might as well do it by hand.
Rice cooker. Too easy to make on the stove or run to the chinese takeout place for a large order.
Tupperware microwaveable rice cooker. See above. Also, I lost the instructions before I ever made anything.
On the fence about:
Kitchenaid. Okay, I know I'd love it if I could get to it. It's in the back corner of the kitchen with stuff piled on it because it was too heavy to move out of the way. Now, I just can't be bothered to clean things up to get to it and use a hand mixer for the few times I need it. I just don't bake all that much.
Vitamix. I used it at first for smoothies, but fruit is expensive to just mash it up and drink it. And we don't always have ice, so that's a problem. I do use the dry container to make break crumbs, though. I wonder if a cheaper mixer would do both jobs just as well?
Pressure cooker. I've used it for stew on occasion and for beef bone soup, to speed up getting the goodness out of the bones. But I still have to boil for another hour on regular heat after depressurizing, so not too much of a time saver.
Slow cooker. I use it for chicken soup. The only good thing is I can get a cooked chicken from Costco, get it home, debone it and toss the bones in the slow cooker all day (with a few veggies) and have soup and sandwiches from the chicken meat for dinner. But most other things I've made are too much morning work (like PP said) to bother.
Things I love :
Breville Citrus Juicer. That was one of my best purchases. Fresh and easy juice with an easy clean up. And I can do a lot of oranges/lemons at once without the motor overheating (like my cheap one did).
Kenwood immersion blender and potato masher. I would never go back to hand mashing potatoes again. I bought one for my 80 year old mom and she says she finally can mash potatoes again. Her arthritis would hurt when she tried to do it manually.
Foodsaver
This has kept so many foods from going bad in my freezer or fridge. I use it to repack all my meats that I'm not going to use up right away.
