Is there a more elegant way of adding an item to a Dictionary safely?

Just use the indexer – it will overwrite if it’s already there, but it doesn’t have to be there first:

Dictionary<string, object> currentViews = new Dictionary<string, object>();
currentViews["Customers"] = "view1";
currentViews["Customers"] = "view2";
currentViews["Employees"] = "view1";
currentViews["Reports"] = "view1";

Basically use Add if the existence of the key indicates a bug (so you want it to throw) and the indexer otherwise. (It’s a bit like the difference between casting and using as for reference conversions.)

If you’re using C# 3 and you have a distinct set of keys, you can make this even neater:

var currentViews = new Dictionary<string, object>()
{
    { "Customers", "view2" },
    { "Employees", "view1" },
    { "Reports", "view1" },
};

That won’t work in your case though, as collection initializers always use Add which will throw on the second Customers entry.