Simcity Socities is all sorts of awesome after all the patching that Tilted Mill did for it. Great game, nice "progression" via the different objectives and goals, lots of fun. If you were playing that CotN demo and looking for a game that sorta hit the same vibe in a bit more lighthearted way , SCS is a good pick.
Avoid the Hearts of Iron platinum, HoI1 is just piss compared to HoI2 and not worth playing (IMO).
Freespace 1 can be gotten w/ an engine upgrade via the hard light productions people for free.
The best part of that dungeon siege pack is being able to run Lazarus, the Ultima V remake :
http://en.wikipedia.org/wiki/Ultima_V_LazarusBut yeah lots of good stuff there, my big thing is that I own most of the games already (same reason I barely buy anything from GOG).