Heeey, fellow snake! :)
I also got Gryffindor on some other website first, but I guess I must have corrupted a bit in the mean time (must be all that fanfiction I'm reading! ;)) and I got Slytherin on Pottermore. And let's face it, it is the "official" site, so I'm going to go with that.;)
Which leaves me pining for a certain redheaded Gryffindor without much hope, but hey - what's life without some unrequited love?! ;)