When I got my internship for the summer, I began using Microsoft's Visual Studio pretty heavily. Before this I had had some experience with Dev-C++, but mostly I had just dealt with Eclipse. I found Eclipse to be useful, but it was a little hard to learn. Of course, it is open source, which makes it attractive to many programmers. I hear a rumor Visual Studio may also become open source, and will be available on Linux; I don't know where to even begin there. IDE's can be of great help, I know that I use VS for debugging, finding references, going to definitions, and the good ol' Intellisense every day. Basically, if you are working on a large project, an IDE is a must. I've posted some links below on some forum conversations about IDE's, feel free to take a look.
ProgrammingForums
CodeCall
Mary's desk
4 days ago