To start with, I want to mention that according to me an important invention is a thing which changes peoples' lives. Either for good or for bad.. sometimes both.. but it always is significantly influencive for our lifestyle or the way of thinking.
The examples can be multiplied, but I'm going to describe only some. So let me start with the wheel. If I remember correctly it was invented about 4000 years BC in the ancient Mesopotamy.It has definitely made our life easier, because humans could transport some heavy stuff.Nowadays this invention has many more ways of usage, and for instance, probably the most common one, we can move by cars, indirectly thanks to the invention of wheel.
Ok, so the next one, which I want to talk about, is connected with our verbal communication. I would say the language is absolutely remarkable thing for us. Personally, I can't imagine my life without the possability to talk. It's even hard to presume what would happen if the human race forgot the language for a day or two, isn't it ? I mean presumably the vast majority of people don't even think about this invention as an invention, but in my opinion the importance of the one is undoubtedly gigantic.
The last but not least is the computer and frequently associated with it the Internet.This stuff is the thing of only last decades. But the influence on us is probably unprecedented. Not only has it made our life easier, but also a computer is a thing which you can find in almost every house in the world. On the other hand, one must admit that there are some bad issues about it, some bad concequences, like possability to get addicted or having problems with eyes or a spine.
To sum up, I must say that there is no such a thing like an ideal invention. As I said at first you can call something an important invention, when it changes peoples' lives and the above-mentioned do. If you ask me, I'm the representant of so-called 'computers generation', and so that has probably made my life as it is now. And consequently, I'd say the last of the described ones is the most important for me.