Can't say I'm collecting Trek stuff anymore. But I do have all the movies and all the series except Voyager on DVD. I have soundtracks for TWOK, FC and ST09, a number of books including the Chronology, the TSG tech manual, Scott's Guide to the Enterprise and The Star Trek Compendium by Allan Asherman, the two Countdown comics, and I still have a number of model kits and toys. I also have Star Trek Legacy in the XBox 360, the FASA role-playing game plus a few supplements, and the Decipher role-playing game and two supplements.
I think that's it. I used to have a few more books and models but I threw them away for space, and also because the internet provides most of that information anyway.