There are technically three flash packages.
It gets a little confusing because there used to only be 2, the one for IE which is the ActiveX and the "plugin"(NPAPI) version which is for other browsers. There is also now an APAPI version which Solarwinds does not give out packages for that I believe is for Opera browser but I could be wrong I just know I dont use it.
So then you have the choice of exe or MSI. Typically you will always want the MSI. Windows installer uses msi files and an exe is just a package that contains one or more msi files and could contain other files to be installed. MSI files are typically easier to uninstall since you dont have any bloated software or unknown registry changes to worry about removing and MSI directly supports certain commands from a command line.