From what I've seen, and once being a systems consultant, and now being embedded in an old client, I can say you really need to have exposure to business to answer that question yourself. The most successful solutions I've seen are created by a person or (even better) a large group of people who come from an industry and already have groundwork expertise in that industry. You can "grab the ear" of an embedded experienced person, but then why would business owners, C-level execs, VPs, or engineers not just create the solution themselves? (aim to become one of those people)

Here are a few generic super-saturated software solutions I've seen:
- Issue tracker: anything from helpdesk, to facilities management, to bug tracking, to project management and everything in between.
- Accounting software: Yes. Accounts payable, accounts receivable.
- Stock tracking: I'm a vendor, I'm a distributor, I'm an end user... all still relevant to me! (integrate into the other stuff, for sure!). CRM would fall into this, if you're crafty with your nouns.

l0gicpath already expressed the value of a thread like this, I doubt you will get specific answers to your specific question. Humbly, I believe your best bet is to connect with people involved in businesses (in real life), try to focus on an industry, and see what's needed there.

I've been working with this client for almost five years, and I can say I have several ideas of what's needed for them. But as with l0gicpath, I can't share them...

Here's a magic path:
1) Start focusing on a thing you like doing: coding, working on cars, painting, a trade, furniture design, music, ceramics, clothes... (sorry I'm looking around my room)...
2) Start working harder on that until you understand business operations a bit more.
3) Find a niche that needs filling and fill it.
4) ???
5) Profit.

I'm on step 2 and have been working for nine years generally in two industries. Many people don't have the motivation to move passed step 2, or arguably never even complete step 1 (just live a mundane life collecting a paycheck in something they don't actually enjoy). Some people are able to bypass step 2-3 by riding on other peoples' coat tails (like working for a company that does this thing). Then they expand just beyond what the company does, sort of like: http://matt.might.net/articles/phd-school-in-pictures/ and blammo... you've got a business.

Here's a trivial example of the magic path... I just remembered an ad on the NYC subway about a dude who graduated from Monroe College in The Bronx and opened a dry cleaner:
http://www.norwoodnews.org/id=11530&story=monroe-graduate-op...
http://www.stopanddropcleaners.com/v1/

He saw a pretty saturated niche service, used some business-analysis stuff to figure out where to put the service, filled it, and now he's running a successful business. If he has the business acumen, his business will grow, and he will make more money. He will spend it on himself, or on his kids education, and he will start the long line of Jimenezes, successful dry cleaners.

Tom Cat Bakery, Shake Shake, Dewalt, Seguso glass, github, Google... they all started somewhere and provided something to some clients. They all had motivation, controlled risk, and had some insight into their customers' needs and wants.

You can do the same with hard work, perseverance and motivation! I've followed you on github and look forward to seeing what you produce!