From the things not already addressed by Awesomemod, here are my pet hates:

CreateHousehold without MoveIn (and other events that result in vagrants). 
MergeHouseholds - I'm constantly going into Edit Town to split out the stupid move-ins that take place.
AddSim where the Sim is some random non-spawn.

Oddly enough, ThrowHouseParty is the one feature I actually like (assuming there's a chance for one of my actives to get invited), yet have never encountered.  Didn't even know it was possible until I saw it on the list.

I've actually been quite pleased with the way my born in game Sims are turning out.  A few have had awkward periods (or really unfortunate hair choices that made them look much worse at the outset), but almost all of them have grown up to be rather pleasing looking.  They're not all classically beautiful or handsome, but I've seen nothing even approaching the fugliness TS2 would throw at me.  And I've said it elsewhere, but almost all of the fug I've encountered has been realistic fug - the kind of ugliness you're likely to encounter walking through the mall rather than the house-of-mirrors type.

Except for the Bunch clan.  They're just F-U-ugly.

This might be observer error but one benefit to TS3's potty training is that they seem to train for a fixed amount of time, regardless of bladder levels.  It used to be that you had to wait until the last second to train if you wanted to get in more than a few game minutes of training in, but now it looks like it fills up about 1/4 of the progress bar regardless. 

Not necessarily - using the original standards of the test, it would be fairly easy to determine, possibly after several tests, whether hair color changes during pregnancy had any effect.  With the completely bizarre, clearly recognizable colors I was using, if a Sim changed her hair color during pregnancy and the spawn came out with the same hair, it would be pretty definitive. 

Through a stroke of bad luck, I actually got a chance to test this myself today.  Merging a Sim in then moving them back out resulted in the missing toddler appearing near the front door.

Rock stars do indeed also get the "Sign Autograph" feature, as do star athletes (I can't remember the exact title for Level 10 in the athletics track).  Star athletes additionally get the ability to do advertising deals, apparently.  It was available for my star athlete with the bookstore, but I stopped playing her before ever trying it on other lots.

Apparently it doesn't - I suggested trying that when someone else had the same problem and it didn't work.  Someone else then posted the solution I listed above which apparently does work.  Resetsim seems to be mostly for getting Sims out of stuck actions.

I've read that if you merge a Sim into the household, the missing baby will reappear and be back to normal.  You can then move the merged Sim back out.

The difference, of course, is that The Honeymooners was made decades ago.  What was funny once is not necessarily good material for humor today.

Says who?  TS2 base was 5 years ago, and for many players, many, many dollars ago.  Where's this rule that says we have to accept being given as little as possible in the base game just so they can milk more money out of releasing the same recycled EPs?  How about they start giving us more value in the base game and concentrating on actually delivering new, interesting content for the game they've promised would be such a remarkable evolution from TS2?  I don't feel like spending 20-30 bucks on an EP just to get the same exact shit we got in Nightlife or University, etc.

I fully believe it IS Voodoo magic simply because all I have to do is keep reloading the game and eventually it works.  I don't delete cache files, I don't change anything.  I just keep reloading it, and on the 2nd or 3rd try, it loads successfully.  If nothing at all is changing, yet the game randomly works or doesn't, well I don't see how that can be anything but weird voodoo magic.  How do you fix a bug that randomly fixes and unfixes itself, and occurs at a point where the mod isn't even in play yet?

This may sound horribly obvious, but you are adding the cracked files to C:\Program Files\Electronic Arts\The Sims 3 etc., right?  Not the drive you have mounted with the image?

I haven't tried it myself but in another thread someone reported that it does not seem to work in Sims 3 - the child taken was not available through the adoption pool.

If you have Awesomemod installed, however, you can split the baby out of the household and merge them into the new one.  If you don't have awesome mod, you can still do this, but you have to have an adult move with them (but you can then move that adult back out). 

However, this will not reassign the family relationships.  The child will still have the same parents, just living in a different household.

The Bunch family (Arlo, Judy and spawn) appear to be some sort of takeoff on the Brady Bunch.  Too bad every last one of them is fuglier than sin, otherwise they'd be a potential mating pool for my Sims.

There are pictures in the "Share Pix" thread that are ingame (there is an example of weird lighting issues as well as a picture of a woman in a tub that just perfectly demonstrates everything I find wrong with her skins).

Gossip is so weak in TS3.  99% of time, it's "Did you hear so-and-so is rich?  I never would have guessed!"  The biggest problem with that is the game seems to have an extremely low threshhold for who is considered rich - I think just about every Sim's name has come up.

Worse is "Word is that Sim A was flirting with Sim B."  Not very salacious when Sim A is in a committed relationship with Sim B.  Or "Sim Soandso has a dark secret", but when I have Sim Soandso reveal her secret to someone, it apparently has something to do with cooking.  Oh, you deviant, you.

Also, when I was doing genetics testing in an empty hood, my Sims, who had never met any of their neighbors, managed to gossip about how rich Mortimer Goth is, just moments out of CAS.  (I specifically tested this to see if it would be the case).  

To answer the post just above mine - gossip will occasionally mention someone being promoted.

I have parthenogenesis off and slowly (possibly because I have lifespan set to epic?) the nonactives are starting to spawn.  I wonder if there isn't some sort of population control going on; I had 3 Sims die in a Sim week, and in the following 2 weeks the paper reported 1 new family, a new marriage and two new babies.  However, the preceding 6 weeks or so had been completely devoid of any Story Progression activity.

Yep, that'd be me failing at reading comprehension.  Somehow I just wasn't parsing it. 

HP's defaults look ten times worse than the game skins, in my opinion.  Everything she feels she has fixed is a massive decline for me.

How does mood factor in?  Are there any modifiers for sending a Sim to work in a great/terrible mood?

I had the hardest time finding it at first.  If you're looking at objects grouped by room, it's under "Outdoors".  Then click on the football icon (Activities).  The water sprinkler is there.  I guess it's there because Sims can play in it, but it works perfectly well as a garden sprinkler.

I just checked - cattails and lilies are under "shrubs". 

Water plants are just lumped in with regular plants.  I remember seeing cattails and possibly some water lilies.

Yes - cardio lowers the fat slider, strength increases the muscle slider.

For the "pic or it didn't happen" crowd (lowres screen shot):