got rid of mine from my first wedding, which was a pity as my sister made it and it was a beautiful dress. But no way was I keeping something from a dead marriage. However, it went to another sister who is also a talented seamstress so whatever she did with it she was welcome to.
Second wedding: had a trouser suit made by a local designer and wear it together and separately to the theatre, special dinners etc. The jacket is especially gorgeous and I love to pair it with swishy black trousers.
A friend got married in Vegas, rented her dress, and cheerfully gave it back the next day. Everything was handled by the hotel concierge and she didn't have to worry about a thing, including hauling around a big unitasker forever and a day. Took me a bit to adjust mentally to the concept of someone renting a wedding dress (she could have afforded to buy any one she liked) but then the more I thought about it the more brilliant a solution it seemed!
Of course, if you have one and you want to keep it by all means keep it. If so, there are drycleaners who specialize in wedding gowns, use them!
If you don't want to keep it, sell it on consignment at a second-hand/consignment shop and use that money for a symbol you DO want to keep. Personally, I would buy myself a piece of jewelry to wear, and call it my "dress" ring, or whatever. It gives me such a dread, sinking feeling to keep what I feel society expects me to cherish forever (cue '70s Kotex ad imagery, running in soft focus over a field of daisies--and I can ride a horse and SWIM with a ring on, too!)