I have made a list of games mentioned that sound appealing - could you please point out which are really good for 2 players?
**Dominion - Good with 2
**Mage Knight - I've only played with 4, supposed to be great even with 1
**Civ the boardgame - Plays fine with 2, but a little limited. We found that we would play too defensively with 2. Better with 3+
**Twilight Struggle - 2 Player only

**Elder Sign - IIRC, if played with 2, you take 2 characters each. I've only played the real game once, which I found to have far too much downtime for such a 'light' game. That said, I love it on Android.
*Settlers of Catan - 3+ players out of the box, there are variants available.
*Ticket to Ride (Europe version + 1912 + Marklin) - Nordic Countries is the best version for 2, Europe IIRC works OK with 2.
*Game of Thrones - Haven't played. I know it works better with more.
*Carcassone (Inns & Cathedrals + Traders & Builders) - Absolutely great

*7 Wonders - 2 players is an official variant, works OK, but really comes into it's own with more players.
*Eclipse - Top notch, probably my favourite game atm from 2-9 players

*Munchkin -Ugh. It's OK I guess, but there's not much of a game there.
*Power Grid - Again, works fine with 2, but far better with more owing to the auction mechanic. There is a 'robots' expansion that improves playability with 2, but I haven't played it.
*Race for the Galaxy - This is basically multiplayer solitaire anyway (controversial!)
*Colditz - No idea.
*Small World - Works nicely with 2.
*Arkham Horror - Haven't played
*Pandemic (+ On The Brink) - Works perfectly with 2, though it does make it easier. You can counteract this by playing on harder difficulties

*Last Night on Earth - Haven't played
Bohnanza - Haven't played, but I've
heard that it plays nicely with 2
Battlestar Galactica (+ both expansions) - 3+ players, comes into its own with 5+
Discworld - Assuming you mean Martin Wallace's Ankh Morpork, I've only played with 5, but I thought was a quite a nice, variable goals and player powers, if a little light (for Martin Wallace

).
** Mentioned as 2 player
* Recommended more than once