I have 3 mods that I cannot play without, I will not start the game without them.
Lock Skill Gain Progress - Make Sims Your Own by Triplis
http://modthesims.info/download.php?t=601844
THIS MOD IS AMAZING!! Yes, I mean that in all caps.
http://thumbs.modthesims2.com/img/9/2/9/0/4/2/1/MTS_Triplis-1726491-bad-cook-main-screenie.jpg
I'm borrowing a pic from Triplis here as a illustration but as the name says. Lock the skills of your sims and make them your own.
For two years I have avoided haven ovens in my sims homes because I got tired of all of the becoming master chefs just by doing dinner daily. I wanted lvl 10 cooking to be exclusive and special for my sim that finished that aspiration. The same for videogames, I put all the computers in the basements in the library and household inventory because I wanted my gamer-sims to be the only ones who got specialized in that. I wanted my sims to feel different. By virtue of playing the game with a very long lifespan all the sims got pretty much high skills. They felt the same, I got bored.
http://thumbs2.modthesims2.com/img/9/2/9/0/4/2/1/1726492.largethumb.jpg
Now I just lock different skills for different sims and they don't progress anymore. My main sims has an oven in her home and she is still a bit of a klutz in the kitchen even if she makes dinner every night. I <3 this so so much. I can start placing items freely in the game again because the sims that I don't want to have specific skills have those locked. They don't feel the same any more. I look forward to playing my sims who are specialized in different skills because they are different.
@Triplis , you are a hero!! :)
No Happy Environment Moodlets by roBurky
http://modthesims.info/download.php?t=591054
It just makes such a difference to the game, your sim will start to feel bored, sad, angry and not just stay "happy" through everything.
MCCC
To big to explain quickly here. It is great, if you are mod-curious go into the gameplay-forum and look for the MCCC-thread