I mention all this not to brag but to encourage everyone to go to a conference. Conferences rock! They get us away from our computers and into real-life human interactions with other writers! They rejuvenate us, get our creative juices flowing!
If that's not reason enough, they have awesome networking opportunities. You never know when you might help yourself or someone else along the path of success. Last year, for example, one of my critique partners sat at my networking dinner table and ended up having the agent ask him for his manuscript. Huzzah! I've even seen folks set up on-line critique groups in the bar!
There are a large number of conferences. To be the most effective do your research. Where will your ideal agent or editor be? Where will you be able to pitch to said agent or editor? Actually, for SF and Fantasy writers something to consider is: Nebula Awards Weekend. This is chock-full of industry professionals and for some reason few writers go.
Another tip: for the biggest bang for your buck, volunteer. Often this results in reduced or waived conference fees.
Anyone know of any good conferences?