Breedables made my SL experience what it is. Until I got into them, I was basically spending all my time tromping around, shopping, renting houses, furnishing them and tearing them down. Fun enough, but very lonely.
When I started with breedables, I was drawn into a community of fun, friendly, supportive folks (and a few cut-throat ones, just to make things interesting. :smileywink:) Plus, I made enough money that I'm still supporting myself in SL more than a year after selling all my breedables off.
RL interfered, making the whole thing a little too much for me to handle. (They do require a goodly amount of attention if you're going to profit from it). And I wouldn't recommend them as a surefire way to make money; I caught some lucky breaks and was the beneficiary of extreme genorisity, which I have tried to repay. But I do recommend them as a great way to make friends.