I really like the upselling versions thing - which is starting to get more common on Steam, which sell the NEW re-released version (likely w/ more expansions and/or DLC) at a reduced cost - which often seems to be at 33% off.
i.e. STALKER series (STALKER: SOC or Clear Sky owners get a discount if they want Call of Pripyat); upgrade Divinity 2 from Ego Draconis to DKS Edition; upgrade Blood Bowl: Original or Dark Elves Edition up to Legendary Edition.
Also, absolutely agree w/ this:
Don't
1. ...double dip DRM.
If your title is on Steam, you should not require GFWL sign up, or bundle SecuROM/Tages, or run a separate key/activation server for the single player portion of the game. All of this functionality is already provided by Steam, and every level of DRM added is added is a barrier to purchase, not to mention seriously hampers usability for the legal owner of the game.