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.