Carcassonne (New Edition)

An excellent gateway game! Quick to learn and teach. My wife, who prefers light games, asks to play regularly. Expansions add more complexity, if desired, but aren’t necessary to enjoy this game.

Bought for a friend, he hasn't opened it yet.

I enjoy playing the game. Young and old are able to join in.

I grew up playing Monopoly, and I remember seeing this box in a hobby shop one Friday Night Magic -- it had derpy looking box art (first edition), but since I had won the draft that night, I used the leftover cash on this instead of the extra booster packs -- an excellent decision.

Carcassonne is a very relaxed game: Draw a tile, place a tile, then decide if you want to place a meeple (also first time I saw a "meeple"). It plays well with non-board gamers, and "gamers" have enough to think about where the best player will come out on top if they want to turn on the analysis. There are a few house rules I like that make the game "thinkier" but it's totally unnecessary. This is definitely a lighter game, and there have since been newer more complex tile-layers, but Carcassonne just has "it". Seeing the world grow as you build the map and seeing the meeples populate the table is satisfying. However you can also play a meaner game: connecting your meeples into your opponent's area and stealing all of their points, adding tiles that make certain areas extremely hard to complete... like I said, the game has enough going on to keep it interesting, without getting too fiddly to slow it down (not that slow fiddly games can't also be good).

I would recommend the Inns/Cathedrals (at least) and perhaps Traders/Builders if you're looking at expansions that add to the core idea of the game. Some of the others get too wacky for my tastes.
I prefer the artwork of the older version (less-saturated), but the new version is fine -- get whichever version comes at the best price.

Easy entry into tile placement games, once you get tired of the vanilla base game, there are many expansions to increase complexity.