I can only answer a few, since my experience is limited. I try my best to recall some of the things I know about the subject.
Computing:
Awesomeness: Totally!
I did some programming in .NET C# (my main language) and Visual Basic (not too much, just grasping the similarities with C#), also a bit of Java (fixing codes and debugging only). They are pretty much interesting to the point when you find a lot of bugs you did not expect. Making concept and writing is fun, but debugging is hell. Updating is even worse. I stopped programming ever since. But it gives you the sense of l33t-ness amongst self-calling "modern world" people. Imagine solving your everyday problem, or finding problem just for the sake of making program to help you solve that. During my programming years, i often write useless software such as random-breakfast idea generator, GPA calculator, and such. It is all pointless since it could take me some 3-5 hours to write one, but the utility is none of the matter. I create them just because I can. There is no limit in this, just pure creativity.
Career path: Suck.
My friend landed in one of the top 5 multinational IT consulting company, the pay is so-so, but the workload is ZOMFG, so she went into another employer, there is a pay increase due to her previous experience with the top 5, but the job remains the same, probably forever.
You can also try to make games, or work for a developer. As the career progresses, if you show some management skills or leadership, you might become the CEO. But this is very rare case. Most of the times, you end up being chief programmer or something like that.
Best option:
Try your luck by making some great software or website like Bill Gates, Sergey Brin, Larry Page, or Mark Zuckerberg and be multibillionaire. When you got l33t skills, you don't work for someone else, you gotta work for yourself.
Economy:
Awesomeness: So-so.
This is like being jack-of-the-trades, while experts-of-the-none. Economists (like me) are mostly bullshit, since they rationalize everything that happens everyday and include it in their science. Economy involves the understanding of your favorite subject: e.g. consumer business & transportation industry (for me), or green energy, or automobile industry, or natural resources (mining, oil & gas, etc), medical, basically anything that runs for money. So economy is not just about trading, marketing, finance and accounting.
Economist tries very hard to understand the subject they don't even know shit about and direct resources (money, of course) to that sector. Economist built their expertise on various ways: formal or informal education. Personal interest or professional interest. Anything goes.
I have an ex-nuclear engineer friend working as a marketing guy for securities company, he is always in favor for non-polluting industries. The other is an ex-pharmaceutical industry guy, he advises wealthy people on which drug company is good for the money. Me, I fix companies most of the times, telling them where to spent their money and effort in order to improve their performance.
The only awesome thing about economy is that it never gets boring. It is not like in the TVs where you got people sitting all day behind desks or yelling to each other at a stock market. But you meet people of different interests, different aspects, different world. I recently get into NGOs, helping jungle people establish their economy. It is like playing farmville or tycoon games with real people. Telling them how to report their financial, how to read the indicators, and how to expand their business.
We pride ourselves in our understanding of financial world, something that so many people in the world are ignorant about. Some financial tools like derivatives are utterly complex. It took us 2-3 courses in a financial degree to study about derivatives. But when things go too complex (clusterfuck), you can always draw yourself back into the good old principle of simplicity: it always worked in economy.
Career path: Great.
Think about the highest paying job of all? It is not sales commission you receive out of selling stuff for other people, but by managing funds, handling other people's money, rich people's money. Hedge fund managers is officially the highest paying job in the world, you can earn $800 million a year, including all the bonuses. Economic downturn won't affect you, as long as you stay in the right path (positioning against the market in bad times or put your money in the most sustainable business like Warren Buffet does).
If you are to confused with investment world, you can always go down into business world, running business operations, managing its financials, or even running a real company. Most CEOs of big companies came from economic degree, discounting the fact that Bill Gates (MSFT) took law degree he never finished. Some do came from other school like engineering (Rex Tillerson of ExxonMobil and Mike Duke of Walmart) But guys like Peter Voser (Royal Dutch Shell), Jeff Immelt (GE), Akio Toyoda (Toyota), and Warren Buffet himself (Berkshire Hathaway) studied economics.
Best option:
Economics leave you with the widest career path available for you to choose. You can be an NBA player with an art degree or Dinamo Zagreb player with an anthropology degree. But economics degree will lead you somewhere if you don't really know where to go to.
Informatics:
Awesomeness: Nah!
This is actually my first degree. I studied the so-called "information systems", it turned out to be "an IT guy trying so hard to understand business world." Kind of, football fans trying to understand rugby rules. This is all about IT meet business, geeks meet the real world, when Sheldon from "Big Bang Theory" don a suit and talk some sense to people with real business. These guys try to find the answer on how can technology help business run better, grow bigger, predicts the market better, etc. When we say business, it can be any business... war business, monkey business, science business, or money making business... anything that needs information.
This science is the reason why you see people sitting in front of so many monitors on their desk: information. Like economist, IT guy must understand the subject of their interest, then ask themselves: how can a computer help those guys out? E.g. arranging HUD information layout into the most efficient layout ever possible.
During the study, it was compulsory for me to take several accounting and marketing subjects besides computer science courses. Some examples of "purely" Information Systems subjects: database design, system design, (IT) project management, human-computer interaction, and such.
Career path: just OK.
I landed in assurance service for this, making sure that some company's computer that they use for financial reporting is in compliance with some American Senator's passed bill.
Thanks to recent financial meltdown and paranoia that follows after, the job is really on the demand. To this day, they still ask me to do this nonsense.
You can finally land into some company, probably big ones like Fortune 500 companies, and become their CIO (Chief Information Officer). Everything in this path is pretty straightforward.
Best option:
Since you are in that jack-of-all-trades position again, you can't never be awesome enough. What they have to offer is just job safety, you can land on any business of your liking, in their IT division. Any... really, any business, as long as they have computers.
