Currently, the best version of SW is v2.0 - you can either get the AVCHD, which is basically a 7.9GB Blu-Ray you can burn to a DVD and it will play in a BD player or you can get a 15GB MKV, which won't fit on a DVD and can only be played on some players. They are both the same version only different bitrates.
Of ESB and ROTJ, there is only one version so far and that is v1.0.