My main goal is attempting to do it all. All the careers, professions, lifetime wishes, degrees, death types, lifetime reward objects, etc.
Currently (after playing one particular world for seven (!!) years) I have completed all the careers and all the professions to the top level, except the Singer.
There's one LTW that I can't get, even after six or seven tries in different ways, which is "The Ark Builder".
The only other one left to do is of course Vocal Legend, which I'll have once my Singer completes her career track. She's getting there...
There's one death type that I can't seem to accomplish, which is 'Shark Attack'. Sims just refuse to die, no matter how often they get mauled by sharks.
I still have to get a Sim to die of the 'Buried Alive' trick in the magic box, but I am sure I can manage that one. I'm just not ready to kill my current magician just yet. (My previous one died of the 'Watery Grave' magic box trick.)
And then all that's left is to have some Sims form a band and get to the top of that career. I've never, in all these years, had a band.
My second goal (which is the main reason why my 'do it all' goal has taken 7 years) is to play all the pre-mades in all the EA worlds for at least two Sim-days. I'm not very far with that one, because I tend to get sidetracked... I'm currently playing Bridgeport, which is my 9th world in this particular challenge.
I like to leave each world with everyone in the proper career, with a story going, and a properly decorated house. And with all the necessary community lots in place (and altered to suit the vibe of the world, if necessary).
I do not now, and never plan to have, a life. :D