Since I typically can't find a good group of people to play games with here in the UK, i've mostly been picking up games either explicitly for single player, or can be played with a solitaire variant.
I recently picked up Friday (exclusively solo) and fell in love with it over the weekend. Tons of challenging and interesting decisions every step of the way with that game, minimal table / floor space required to play, good value (£14.99 for a game I'll probably end up playing a lot).
The only other one I own would be Space Hulk: Death Angel (which is coop with a single player variant)
Anyone else fans of these sort of games, that could recommend more of this style?