I know quite a few people who don't have one and I just don't get it, I would miss mine loads if it broke on me!
Now, let me just say that we don't live off ready meals. In fact, any ready meals we do get I usually put in the oven as it cooks them better. But you can do soooooooooooo much with a microwave.
DH is fab at batch cooking, so it's used loads to defrost stuff (I have a terrible memory and always forget to take stuff out of the freezer in the morning).
Our hob was out of action for ages recently when we were wrangling with the insurance company, and the microwave really came into it's own then. We used it to cook rice, pasta and mashed potatoes. In fact, we've carried on doing rice in the microwave as for some reason it's easier to get the proportions right and it doesn't come out soggy. We used it to soften onions etc before we popped them in the slow cooker, and it's great for steaming veg.
I cook porridge in it, in bowls so we don't have a pan to wash too. And heat up milk /melt cheese / butter as needed.
I think microwaves are FAB!