I really can't see a significant difference between 720 and 1080 when watch the videos on screen. But editing yes.
Knowing that there are some tv, specially the sports, who decided to broadcast in 720, I asking myself what is the real advantage to embrasse the 1080,
I notice that I end most of the time choosing the 720 for flexibility, but there is this silly idea that maybe I'm loosing a lot of datas.
It's mainly about screen size and viewing distance, and knowing your audience. This
page has the best explanation and chart to show when you should start moving up on resolution.
If your audience will be sitting in front of a computer with a modern large monitor, you can see that going even beyond 1080p would be beneficial. If they're using TVs, most people set their small (60" or smaller) TVs at way
too far away, so there's no benefit from 1080p. I have an 86" (projector) screen for movies and TV, which would benefit from going to 1080p at the ~4 meters I'm viewing at. So I'm getting a 1080p projector to replace the 720p I have now when it dies.
There are other things to consider, though. Compressing 1080p too much can produce results inferior to 720p compressed less. 1080p produces much bigger files and higher bitrates. Most new computers can do 1080p without a problem from online sources, but computers just 1 year ago would have problems with stuttering and dropped frames - graphics card can help if it has hardware acceleration. Also, higher bitrates lead to problems with streaming or downloading for anyone on a capped or slow line.
Also, note that progressive and interlaced is another matter; raw 1080i vs 720p has almost the same bitrate, and some prefer 720p over 1080i.
FWIW, I like youtube's approach, which allows me to choose 480p, 720p and 1080p depending on my bandwidth and what I'm using to watch the video on.