It was definitely one that took some serious time to play through. I remember some of the puzzles being too tough for me when I was younger, so I cheated a lot of them initially and while it was still fun, it skipped over a lot of the great parts of the game. I reinstalled it about a year ago and started fresh with no cheats...it is just so freaking stellar in every way. There was just so much satisfaction when you finally reached the top Visa Level and were finally able to afford a vacation home (btw, I looooove so many of the standard houses you can buy in the other locations). In a lot of ways, it made me wish that EA had allowed the development cycles for expansion packs to be a little longer, because it was clear that compared to most of the later packs, World Adventures (and to a lesser extent, Ambitions and Late Night) were a cut above.
I feel like Generations was kind of a wimpy EP because so much of the new content was patched in even if you didn't own the game. You were basically paying for a glorified Stuff Pack, which seems kinda shitty. Showtime felt like it was made only to give Katy Perry something to promote.
All three worlds are absolutely gorgeous and painstakingly constructed. I think my favorite of the three is Champ Les Sims, just because they captured that lovely French countryside feel so well and it had my favorite tomb (The Landgraab Mansion). The nectar-making skill was also my favorite of the new ones, so that probably contributed a bit. Al Simhara had all that beautiful water and maybe the best story of the three, along with the most consistently challenging and fun tombs (imo, anyway). Shang Sim-La was great to explore and I really liked the Forbidden City area in the center; I'd always buy a house in that area, sometimes by kicking natives out of their home.
I was never much of a builder, so I never tried to make a tomb on my own, but I did download a few homebrew ones, way back in the day. They weren't all quite up to par, but some were quite advanced and fun to play through.