I'm not sure what my highlight so far has been. It may have been having a guy die while making out with me, before immediately proceeding to call up his sister, have a little mourn, flirt, make out, ask out and then dump her, whilst standing over the grave of the brother. Or it may have been discovering the patriarch of the town has a daughter, who I end up going out with, only to dump brutally, before hearing the patriarch has died, chatting up the widow in the gym (I ask her if she's single - surprise, she is!), and flirting with her enough to go steady. All in front of a crowd, including the upset daughter. Before dumping the widow. Only to later, in my dotage, get back together with the daughter and move into their epic townhouse.
Ah, business is good. Or at least slutty.
After playing for a few weeks with this preview code, The Sims 3 is obviously the biggest renovation in the series since its initial appearance. The Sims 2 improved on the original in pretty much every way, but was still fundamentally based on the idea of individual lots - houses, shopping areas - requiring a loading pause to skip between. The Sims 3 throws all that away, and sets the game in an actual living town. People go off on their own daily routines, and you're free to move your Sims wherever. And, in fact, you can even change which sim in the city you're controlling. It was through this that I manipulated the move-in of my first sim to the rich family, thinking it ended the Machiavellian flirt-a-thon's life appropriately.
Fundamentally, setting The Sims 3 in a world just makes it all feel more real. While this is mainly a game about the non-work life - when you go to a job, after driving to its destination, you disappear "off the board" for the length of your shift - that whole life feels integrated and real. There's no longer any oddness like people going to another map, staying there for ages and then returning to their house to find they've aged and no-one else has. It lives. The town ages together. Or stays young, if you've changed the setting to avoid horrible things like death.
Which would be a shame, because Maxis has done lots of lovely things with the afterlife and ghosts and... I'm going to get distracted if I go too much into the details. There's lots of minor stuff to catch your eye and explore. For example, I mentioned disappearing off the board? Well, you don't have to do jobs in that standard way. For example, pump up your writing skill and try writing some novels from home, in various genres, with various success and... I'm getting distracted again.
Let's keep this to the main elements which change everything. Firstly, how the game picks up from the 'wants' of Sims 2. Fulfilling of your sims' transitory wants - everything from making the bed to making out with the neighbour - will earn you lifetime happiness points. Be generally happy, and you'll earn them. You'll earn serious amounts by completing your lifetime wish, the desire you select at character-creation (everything from becoming world leader to being a heartbreaker who's dated 10 people, which explains why I was being so determinedly horrible to the people I was making out with - at least to some extent).
When you have enough happiness points, you can spend them on new abilities for your character. You can become more attractive, better at throwing parties, or have a plentiful bladder with room for masses of urine. If you save enough, you can get some serious toys, like a machine which allows you to transform your body shape at will (body shape now alters depending on exercise and... distracted again!) or a teleportation machine.