Do guests really want wedding favors? Short answer: not really.
Nowadays, tradition is out the window. Instead of potpourri or a bag of mints as a favor, couples are now opting for different keepsakes (if they choose to do anything at all).
One of the most popular wedding favors is a photo booth print. Guests jump in a photo booth (or PhotoBus!) and get to take some fun photos. Usually the vendor puts the couple's name on the printout so that when the guests look back at the silly photos, they remember the wedding. I LOVE taking photos in photo booths. I try to sneak one in right before I leave for the evening ;)
Other popular favors that I have seen recently are Koozies, packets of seeds, candy buffets, and candles. I recommend choosing favors that will be useful. More often than not, favors get left on tables or do not get picked up in the first place. To avoid this, make sure that favors are right by the exit of the building so guests can grab and go on their way out.
Another option is to give a favor that is really personal. At Mika and Bobby's wedding, they gave away CDs. They were dating long distance for a while, and while they were apart, they would send each other recordings of themselves singing different songs. (I know. Too adorable.) They designed the sleeves and gave a disc to each guest. Killer idea.
In 2013, I photographed a wedding at a berry farm. Their favor was jam from that farm. (It was freaking delicious by the way)
Favors are a way for guests to remember your wedding, but more than a koozie or a packet of seeds your friends and family will remember the exchange of promises. They are the witnesses of your marriage.
Whatever you choose, it is YOUR wedding. YOU know what is best for you.