I’m going to put the link first, because the GIS software available there is outstanding, and its free. I have been using ESRI ArcMap for years now, and while it is an incredibly powerful piece of software, I actually find myself leaning towards QGIS more and more recently. QGIS isn’t quite as polished as ArcMap of course, but it is completely free. I have been showing it to some colleagues recently, and they have all been impressed with it, even going so far as to say that it is better than ArcMap! Of course, you still need to know your way around a GIS to use it, but if you do, you can get some fantastic results from QGIS.
If you have any interest in GIS software, go check it out!