Quick summary of ID from an ID grad:
It's a mix of business and engineering lite. ID puts you one class short of a business minor, and many of the IDIS classes are related to running a distributor (though the principles apply to any kind of business). You'll see a lot of things about inventory and logistics management, a survey of MIS, lots about pricing and dealing with relationships between supply chain partners. The engineering-type classes are not particularly challenging, and very "applied". By that, I mean that there are some fundamentals classes like materials and manufacturing techniques, but the upper level classes are focused on learning the basics in industries that tend to hire a lot of ID grads (power transmission and electrical in particular).
As far as employment, there are generally two tracks. One is technical sales, which is probably the most common career. The other is loosely termed "operations", and means dealing with physical inventory, warehouse processes, and the like. There are a ton of options though, which is the hallmark of ID. Personally, I started out in software development and then moved into financial analysis less than two years out of school. Getting back to the options thing, many companies recruit out of ID. They have large career fairs and tons of internships. If you want to branch out from some of the traditional employers of TAMU ID students (off the top of my head, Gexpro, Womack, DXP, and Crawford are annual attendees at the career fairs), you can compete with IE and other engineering majors and business in general or supply chain in particular.
In terms of payoff for effort, ID is pretty easy (although I heard they were going to add MATH 151 and 152 and PHYS 218 and 208 to the required curriculum) and average starting salaries were around 52K when I graduated.
[This message has been edited by Ulrich (edited 2/13/2013 9:02p).]