I'd say that there are seven main kinds of software companies:
Early Stage Startups
Preseed (before funding), Seed, Series A to Series B or so. Your primary job is to build a minimum viable product, demo, or first generation version of the app and acquire early customers/clients. I recommend taking salary over equity at this stage since there's a lot of risk. If you want to live like a gunslinger in the Wild West with maximum flexibility/freedom but at the cost of maximum risk - then this is the place for you. Teams are usually 2-4 people wearing multiple hats. Everybody's got side-projects and it's common for people to sit on multiple companies at a time. Respect for Intellectual Property is very high (unspoken) despite the reputation that some software companies have acquired.
You've made it - you've got customers/clients, you've scaled well. Now you can kick back (but only a bit) as you move to exit (go public or get bought). Make sure you've got solid, non-dilutable, equity! Dogs, catered food, awesome office, flexibility - when you think fun startup this is what comes to mind.
Traditional Office / IT
You might be in a dungeon but you've got job security and good benefits. Most of the crew you work with are older and more experienced. Tech stacks here are less cutting-edge but robust and well-trod.
Security / Intelligence
You might be in defense tracking baddies or being a hacker for good (finding and reporting exploits to companies or other organizations). Your main goal is to secure something (the application, the safety of your country, or your intellectual property). Palantir or cyber-security contractors working for civilian government come to mind.
Here you're working for the big dogs: Facebook, Apple, Uber, Google, Amazon, Microsoft, IBM, etc. Life here resembles a blend of a Traditional Office and a Startup+ - your company is a trend-setter in the software/tech space but it knows how to have fun and attract top talent. Wages and benefits here are competitive with Startup+'s and many Startup+'s are acquired to bring on talent and cutting-edge tools. Intellectual Property issues drive many entrepreneurs into the startup space and traditional perks like 10% "my time" are no longer respected.
Foundation / Research / Academic
Here you primarily do research or produce open-source information. Your objective is to spread knowledge and provide tools for everyone. Wolfram Math, the Apache Foundation, and Node are all examples. Just because it's a foundation doesn't mean it doesn't pay well. These sorts of positions are often the most prestigious - plus, you often don't have to deal with the types of things you'd have to in strictly for-profit enterprise. Many of these foundations are multi-billion dollar corporate entities wielding legal teams left and right to defend their mission.
Consultant / Web Boutique
You work with other developers and help small companies or single clients to build their projects and see their dreams come to life!