Game Packs are actually the most worth it packs out of the three.
If you really want to get your money's worth, I'd say Jungle Adventure has a ton of stuff that will keep you occupied for days.
Parenthood adds some nice new traits to spice your sims' personalities a bit.
I don't really have any tips for a TS3 simmer transitioning to TS4 since I didn't play TS3. But I think the only big difference is the thin UI in TS4. You just have to get used to shortcuts to open and close the different tabs (needs, jobs, etc). Of course, you can also just leave the tab open if you like. :D I just prefer to open it to the needs tab.
Play around with multi tasking and also autofill needs!
