Well, three ways to go here, and the other two picks are both probably more strategic, but I did not want to lose this one.
Jagged Alliance 2 (1999) -- PC
Review
This might very well be my all time second most played computer game (or 5th most, or whatever, behind the Civ games), and it is still the most fun that I've ever had playing a squad tactics game. Just addictive, and the reasons for that are myriad. First of all is the great mix here of role playing game, strategy game, and then sqaud tactics game. The schtick is you are a mercenary captain hired by the dposed leader of a 3rd world nation to retake his country for him (which is pretty dumpy and fortunately only has maybe a few thousand soldiers). You work for a group called A.I.M., and have online access to 50+ mercs for the job. You put together your teams (you can have multiple teams all over the country), and then go to work. You have to clear sectors, conquer mining towns, and get those mining towns up and operational so that you can get enough money to keep on paying your mercs every week. You also need to have medical mercs heal your party over time, mechanical mercs pick locks or repair your worn out weapons and armor, teaching mercs train other mercs or locals. Meanwhile the enemy counterattacks your towns in waves, there are side quests, you can train local militia to defend your towns etc. You even get to create your own custum merc (who is "you" to elad your teams). The second addictive factor in the series are the mercs themselves -- like a great movie, its all about the characters. And what makes this game so fun is that your mercs aren't just random groups of stats, they all have very distinct personalities and some of the best voice acting in any game ever. You've got badass pros, rank amateurs, and everything inbetween. Some are psychos, some are cowards, some hate each other and won't work together, some love each other, and they all spout hilarious lines as they are getting shot, setting mines, kicking people in the head, or blowing them away. And finally of course is the fighting itself, which is turn based (the game is real time until a fight starts) and loads of fun. Especially in the early going when you have to make do with crappy weapons and shaky mercs. I've beat this game and every expansion and user mod, and for several years there kept on fiddling around with this idea I had that if I played the first day just perfect, and somehow mugged this crime lord with a boat load of cash (and a Steyr AUG -- very useful in the early game) you find off to the West surrounded by dozens of cronies with my underequipped ultra cheap initial crew, that I could accumulate enough money to hire the very best of the best and make a huge push for the capitol within the first week. Never did pull it off. But stuck forever on an island, will have plenty of time to work on it.
I need all the consoles to draw folks away from the PC. 
