Lol. Zoloft actually boosts my sex drive. Adderall has the most wreckingball effect on my sex drive out of anything. I almost NEVER have any intrusive or impulsive sexual thoughts whatsoever when I am on adderall. Its like I almost have to force some sexual thoughts in my head every once in awhile just so I still feel like I am human. Thats not to mention the, uhh, draining effect of amphetamine either.
Otherwise, I believe Paxil is known to have the most highly detrimental effect on sex drive (of SSRI's at least) as it is the most potent inhibitor of Serotonin reuptake. Higher serotonin levels tend to be associated with decreased libido whereas increased levels of noradrenaline and dopamine tend to raise it. These two neurotransmitters also have significant functions in the trigger of and pleasure of the ejaculatory response. Zoloft is a partial inhibitor of dopamine reuptake.
I can't believe this hasn't been said yet but getting rid of your sex drive does not really sound like a real good goal to have at the top of your list. I know first hand how uncontrollable impulsive obsessions bombarding your mind is pure torture as I also have some strong OCD tendencies so I feel your pain. A much healthier goal however, would be to get your obsessive thoughts under control with the help of meds so that you are not so uncomfortably bombarded with impulsive thoughts but still have a healthy sex drive. Fortunately the treatment of OCD and the reduction of sex drive sort of coincide as they both usually involve raising levels of serotonin. Ironically, you would probably still be headed towards the right direction even if you just focued on obliterating your sex drive, lol.
I also hope that your situation is not rooted in any sort of conditioned shame for having natural sexual thoughts. Having thoughts that could get you into trouble with the law of course takes on a whole new set of issues, not that I am accusing you of having these (nor that they either should be a source of shame for someone having these types of thoughts who recognizes they are wrong, does not act on them, and seeks help for them). I was raised as a Catholic and unfortunately I bought into the crap that having perfectly natural and healthy sexual thoughts was a 'sin' for a long time and it did a lot of long term damage to my mental health before I got old enough to recognize the hypocrisy and nonsense of much of what I was being taught. OCD style impulsive thoughts however obviously don't require that any sort of religious brainwashing has taken place in order to be really uncomfortable and annoying.
I don't know what meds you have tried but Luvox is a med indicated for treatment of OCD. As far as I know however it is just another SSRI like the others. Therefore I would probably go with Paxil as a next try as it inhibits the reuptake of serotonin more potently than anything else which might help your OCD as well as lower the intensity of your sexual impulses.