it looks like sex is the answer. I guess the reason for this is because to take an E all you gotta do is make a phonecall (it can be the same for sex, but assuming u dont have a girlfriend and you want it to be "special" =p)... or im sure all of us frequenting the ecstasy forum have a few hits laying around, waiting for the right occassion.
However, if you dont have a girl that you can have hot, passionate, great sex with (_with consent_ ), you'd take the sex over a single roll...
I guess in both cases it depends on the availability of BOTH DRUGS =p. With easy availability for sex but not X, it will be X.
And vice versa..
P.S. If somebody is gonna argue as to whether sex is a drug or not... i guess its more like a pro-drug. But yes it is a change from the state of mind of normal boring unhorny sobriety. Even getting a boner is a "drug". Something in your mind and your neurochemistry is being released to set off that boner. and whatever it is that creates the feeling of orgasm... I wish it could be replicated with a drug (and NO heroin is not an orgasm, neither is mdma... altho both seem pretty close).
An orgasm is actually kinda like nitrous now that i think about it... not really the way it feels but the duration of it and its onset and "cumdown" =p