cactuses!??

woah,when did cactuses become an accepted pluralization of cactus? for years i have listened to people terrorize each other over not using cacti to pluralize, and now, this morning, i decided i was fed up with the arcane pluralization, i decided it was time to take a stand, to proclaim my full disdain for this ugly and awkward pluralization and my intention to incorrectly pluralize with cactuses, to set a new trend, in the face of future terrorization and having to explain my position over and over to people.
before making this proclamation, i wanted to have a look at the word origin and perhaps a stab at understanding just where cacti came from. to my surprise, cactuses is listed as the pluralization at dictionary.com and at the oed.
so, it seems cactuses has gone the way of ain't and so many other words of the vernacular and not of the dictionary. my coworker says he will keep using cacti because it's correct, but i'm going to make the effort to start using cactuses. it isn't a word i use often and it may take some re-training of the brain to think of it before i say it. but i don't see a need to ride the intellectual high horse on this one. this is how language evolves, and cacti is as irrelevant to our time as "the gods" are.