A game that regularly hits my gaming table is Power Grid (shown in the picture with the Power Grid: New Plants Expansion.
In Power Grid, each player takes on the role of a power company that is attempting to power the most cities. In order to do this, however, he must both own power plants to generate the power and build enough infrastructure to transmit the power to the cities. How this works in game terms is that at the beginning of each round, new power plants will be auctioned off. After this, resources will need to be purchased to power the (non "green") plants. Third, the players will purchase "cities" (which represents bringing power to that city), by paying the connecting cost from one of their other cities plus the cost to build the city itself (10, 15 or 20 depending on how many other players are already there). Finally, each player will power their cities and generate income (and the resource market gets restocked).
There are several things that I like about Power Grid. The first thing I like is the mechanic where whoever is in last place gets an advantage for that round. This seems to be a trademark mechanic for Friedemann Friese (the designer), because I have also seen this in Furstenfeld. Either way, I like it as it adds a new level of strategy to the game - when should you go ahead and take the lead (and have a slight disadvantage) as opposed to purposely staying behind. Fortunately, the advantage given to last place is useful enough that it is worth sometimes staying behind to acquire it, but small enough that it does not prohibit someone from wanting to be in the lead. It is an incredibly nice balancing element that keeps almost every game of Power Grid very close all the way until the end.
The next aspect of the game that I like is how the auctions work. In many games, there are a certain number of whatever that are available each round. Starting with a certain person, they choose one of the things to auction and once they have bought it there is one less item available on the market. In this situation, the person who picks last has a bit of a disadvantage because they have no chance of getting something at list price, and their options are also very limited. This is not the case in Power Grid. Instead, you can see both a "current" and a "future" market of power plants. Whenever a plant is purchased from the current market, a new plant comes out and the cheapest one from the "future" market goes into the "current" market. This does two things: it makes it advantageous to go last (and hence the person losing gets that position), and it also makes you strategize when you want to lose auctions in order to get to the plants in the future market. Again, this is a really nice mechanic - I like it a lot.
Another pro of the game that keeps it balanced is the diminishing returns on powering cities. For the first city that you power each turn, you get around $15. However, if you power 20 cities, you get $2 more than if you power 19. This is another aspect of the game that keeps it very balanced and keeps all of the players close together throughout. Also, this gives the players more to think about - should I burn the resources to power these cities this turn, or would it be better to keep them just in case (the winner is the person who powers the most number of cities on the last turn). After all, sometimes you can actually lose money on powering cities if the resources needed are in high demand.
Overall, I give Power Grid a 9.5/10. This is one of the best games that I have played. I was incredibly skeptical when I saw the theme (I used to work for a power company, and so I didn't think it was very exciting), but it is a well balanced, well implemented, innovative game that I have thoroughly enjoyed. If you have never played Power Grid, I think you should either go buy a game or convince your friends who have a copy to bring it so that you can play it.
For some more opinions on this one, check out Games With Two's Power Grid Review, or this other Review of Power Grid by Play Board Games. Alternately, for even more reading, check out my thoughts on Mice and Mystics, Risk Legacy, and King of Tokyo.