This is a question that I've been pondering over for quite some time. The only reason for using VS over any other editor, is the help system. But wait, what help system? My point exactly. The help system that comes with Visual Studio 2010 is a very small subset of what the full MSDN Library used to be. You might be asking, "What do you mean by 'MSDN Library used to be'?" Well, somewhere around the time that Visual Studio 2010 was released, Microsoft decided to make changes to the Online MSDN Library, which is now our only source for the MSDN Library. There is no offline version of the MSDN Library anymore. On top of that, a very HUGE portion of what was in the MSDN Library, is no longer available online.
What does this mean? Well, it pretty much means that we are all screwed until Microsoft decides on what they are going to do. The Microsoft Help Viewer 1.1 works for the most part, but has serious issues when dealing with mutliple release versions. Additionally, only a fraction of the Online MSDN Library is available through it. If you switch Visual Studio 2010 to online help, the context sensative system is limited to the exact same items that are available offline, even though the Online MSDN Library does have more content, limited though it is. The easiest way to see how limited it is, is to press F1 on an HTML element while editting an HTML document. Very helpful isn't it? NOT!
The bottom line is that there is no compelling reason to use Visual Studio 2010. The context sentative help system, tied to a FULLY populated MSDN Library, was the ONLY reason for using it. If you haven't started using it, I would say, "Save yourself the $5K+, per developer, per year, license and use something else." I haven't looked for alternatives to Visual Studio in quite some time, but it's time that I do. If you find any really good options, please post them here. But please don't post stupid little editors that aren't fully integrated and don't fully support TFS.