I pretty much stopped playing the originals when I bought Sims 2 because of one important feature: Aging.
In Sims 1, I'd always end up drowning my family's children because of how frustrating they can be. Always the need to do homework, always complaining for the slightest thing and their voice.
Either drowning or using firecrackers inside a shed outside the house. Always fun.
Right now, I'm with Sims 3 which I find better than Sims 2 and Sims 1. They only get better after each title. But I'll wait until they do some sort of mega pack with all the expansions before buying, as I've done with Sims 2. Now that Sims 3 is on Steam, there might be nice deals eventually.
I did like Sims 1's Making Magic expansion though. It was a nice change from the main gameplay.