This one started on Ship of Fools
Readily available contraception IMO leads to massive good to the point that those trying to oppose it are (albeit unwittingly) siding with evil.
I tell good from evil by their fruits. So what have the fruits been? Health, sustainability, feminism, and a greater respect for the sanctity of human life. Oh, and a few more people having voluntary and consensual sex.
Feminism (and other female political involvement) has been one of the consequences of readily available contraception because it has given many more women the freedom not to get pregnant, and hence to do other things with their lives. I believe that allowing people to use their (god-given) talents is (normally - I'll make an exception for Hitler and a few others...) a good thing and that preventing them doing so on the basis of birth is a bad thing. (I don't identify as a feminist due to a number of polititical disagreements - but have no problem with this section of their stated aims).
Sustainability - due to developments in healthcare and public health (starting with sanitation and vaccinations), the chances of an infant living are massively higher than they were 150 years ago. Yet women are still pretty fertile. We also have a massive population on this earth. We therefore need to keep the birthrate down to an approximately sustainable level. There are a number of ways we can do this - we can repudiate the advances in healthcare (over my dead body - perhaps literally), we can try educating people not to have sex (and just what is the success rate for abstinence only sex-education these days? Last time I checked it was almost non-existent) (we could simply educate them to have gay, oral, and anal sex...), we can kill any unwanted pregnancies or use the exposure methods of the Greeks, Romans, and others to kill unwanted babies, we can fight continuous wars to keep the population down (again, over my dead body), we can implement Chinese style policies, or we can supply contraception. If we don't do any of the above, our population will once again get completely out of control, and with such a large population we have much less margin for error.
Health - first it's a massive boon to the health of the would-be mother to be able not to be pregnant. But even more than that, it cuts down massively on the overcrowding which would be a problem leading to disease even if there were no sustainability concerns. And it also cuts the crime rate in the same way (and to a much greater degree) as legalised abortion. (And that completely ignores the effects of condoms on STDs).
Finally the sanctity of human life. There is much more regard for the individual if there are too few people, and much more regard for others if the individuals feel that they themselves are wanted. A murder of anyone becomes much more serious, as does a famine (look at the 19th Century Indian famines). Also the sanctity of life will be considered greater if each individual is not competing with each other individual for means of survival.
There's all that against a few people screwing each other who otherwise wouldn't. (And recreational sex was certainly popular long before contraception became easy - see the Karma Sutra, Penny royal, and prostitution for good examples).