I'm a simmer! check me out...
I LooooooooooVE Sims3!!! Played 2 ALL the time and had almost all the expansions. I admit that I miss my families from S2 but I am now in too much love with S3 to go back. LOL I spent a lot of time on the Sims3 forum reading about everything, to begin with. Before you get it you really do need to make sure you can run the program effectively! I haven't had any problems running the game.
EA Min Specs here:
http://forum.thesims3.com/jforum/posts/list/876.page
Check out this site:
www.systemrequirementslab.com
My sister and dd have taken over my game at times also, they are getting as addicted as I am. It is REALLY different in a number of ways.
You don't save your family as a separate game save in the same old town. Each game save saves a version of that town. Creating and playing with a new family will start with a new version of the town. In order to have multiple self-made families in the same town, you create all your families, move them into houses in the same town and then select one active household to play. Yes, you may switch to a different household later on during game play but you will lose certain wants/wishes/challenges that your active sim is currently working on. AND if you don't turn off aging and story progression mode, the other sim households will automatically 'live' without your guidance! Some don't like it but I think it is cool to see your single girl get a roommate, become your coworker, move to a different house, etc. I personally turn off aging cause I like them to live forever
I LOVE the new customization tools, you can practically recolor and pattern everything! Don't like that drab couch? Give it a complete new look for free! You can use the color picker or HEX numbers.
You tell them what to do (from a list of options) while they are at work or school. For example, stressed out and tired of working hard? hang with co-workers or sleep on the job. Forget to do your homework last night? finish it at school. Schmooze with the boss and increase your chances of getting that raise.
Parties can have more than 2 people invited!! lol and they bring dishes over too, what nice guests.
If you love to garden, omg you'll love this!! Grow money trees, flame fruit, life fruit, death flowers, egg-plants, cheese plants, steak and patty plants too!! Fish for shark, jellyfish, angelfish and vampire fish... with garlic of course.
If you catch a Mysterious Mr. Gnome, watch out! He moves while you're not looking.
btw, Pools... you can't drown them now cause they don't need a ladder to get out.

but you can build walls around the edge.
I've taken a couple screen shots from my game and you can check them out to see some of the details. this is my Sims3 page-
http://www.thesims3.com/myMedia.html?action=default&persona=Kswans321