The most obvious answer is "bacon", the next most obvious answer being "love" (some here on the editorial staff would argue that the words are synonymous). Here are things the world needs.
#1- A Reverse Microwave Oven
No, not a freezer. An appliance that I can put my melty milkshake into and zap it for thirty seconds, cooling it back down to the desired consistency. The applications here are numerous, and considering the microwave has been around for over 50 years, you'd think that it's counterpart would be a mainstay in every kitchen by now. The science is out there, somebody make this happen.
If you aren't sold on the idea that this a great potential invention, I would also point out that there are untold numbers of youtube videos featuring people microwaving stupid stuff. And these videos happen to be awesome. By now most people know what happens when you microwave an egg, but what happens when you hyper-freeze it?
If we're lucky, the same thing.
#2- iTunes For TV Shows
Everyone who owns a TV pays for more channels than they actually watch. Instead of braving the ghetto of the internet to find episodes of my favorite TV show, I'd rather just pay for the one channel or even just the one show the same way I do for my music. This is different than Netflix and similar services, since you don't always find what you're looking for on those services and you still pay for crap you don't want. There's a reason they don't package the six songs you want to buy with 1,000 others you couldn't care less about.
A bonus to safe, virus-free TV watching on my laptop is not having to deal with these idiots ever ever again.
#3 More Dilly Bars
220 calories on the end of a wooden stick somehow
sums up an entire childhood.
I realize the world already has Dilly Bars, but I'm saying we need more of them. When was the last time you had one? Better question, when was the last time you were truly happy?
#4 Things That Fly
Flying skateboard, flying car, I'll even take a flying bike if that's all we have. Seriously though, humanity managed to put some guys on the moon back when a computer took up an entire room. Today we have more complex computers that fit in our pants pockets, yet our vehicles are sadly still a slave to gravity and gas prices. I feel like we let the space race generation down a little bit. They were thinking back then, "Wow if we put a man on the moon today, I wonder what we'll be doing in 50 years!" Sadly, the answer to their question is "Touch screen technology that allows us to play Angry Birds in class instead of listening to the boring lecture!"