Sims 1 all expansions, Sims 2 all expansions here (not all the stuff packs, but in all honesty it seems most of the stuff packs lack support for new features added in some of the expansions like Freetime and Pets, so you have to hit up modthesims2.com and see if someone's got a global-config mod to bring the stuff packs current, which just goes to prove EA sucks at making sure a stuff pack is current for an expansion released a year or more ago)...
Although at the moment neither's fully installed, had a little incident with an 8800gt blocking every SATA port, so of course now I'm on my IDE drive (Sata's plugged back in but won't boot cause it's via a PCI card). And the windows install on the SATA's where all the registry stuff for Sims 1/2 is at >_<
So I gotta reinstal them sometime soon. Not looking forward to it, it'd be like 1-2 hours to install it all and around 20gb hd space occupied (that includes the downloads directory which is like 3gb right now) :S
I'd have zero problems exchanging houses/families and whatnot, only real problem is my house design skills suck. Seems they're all box shaped
IF I had to recommend three expansions though? I'd be stuck cause I wanna recommend 4.
1) University. Specially if you're not a cheater (I can't remember NOT using boolprop testingcheatsenabled true), cause it'll add a few days to your sims lifespan - critical cause you can gain some extra skill points.
2) Open For Business. Least now you don't have some dead-end job, you've got your own business, although it'll cost you a heck of a lot to actually _buy_ a separate lot for the business (start a home one!)
3/4) Freetime or Bon Voyage, depending on if you want your sims to go on vacation, or if you'd rather have the option to have some hobbies (music/dance, tinkering, art/craft, etc.). I dig on both cause Bon Voyage adds a heck of a lot of new objects (doesn't do snowy terrain though - you need Seasons for that, but otherwise BV is pretty much The Sims 1 Vacation), and Freetime lets me buy a restorable car for my sims, which I promptly paint bright yellow or orange and sell to the neighbors for an excessively high price
Plus there's gunna be another expansion too, Apartment Life if memory serves. Not really sure I'm looking forward to that one, but at least it's another expansion before we get to start over with Sims 3 sometime next year.
So yeah, make sure to do your research on the expansions; $30's not inexpensive for most average folk, particularly when there's a bunch of them that amplify the experience (Sims 2 all expansions/stuffpacks is probably like $200-$300, nothing to scoff at).