The Virginia Business One Stop (https://apps.cao.virginia.gov/IDC/index.html). It's not something I have to use very often, but it's on the top of my mind because I just formed an LLC. Its primary purpose is to help new companies get formed in the state by providing a "wizard" to help you gather in one place all the information and forms required by the state and Fed. When I finally found it through word of mouth (it's Flash-based and doesn't show up in my Google search results), I had already formed my LLC but was wondering if there were any important forms I had missed in my manual dredging of the State Corporation Commission's site. I could go on about the poor user experience, but suffice it to say it makes incorrect assumptions, forces repeated data entry, sends you to sites (the IRS) that have an even worse UX and hang without saving, and makes you pay $20 for the privilege.

On the plus side, I've now gotten my first bad business decision out of the way.