I know Foursquare is more popular but please add Gowalla too. I will love you forever. :)
I would love it if there was an RSS feed of my photos. For external services like flavors.me, or even to pull-into my blog.
If I can use API, I will write #NewTwitter Instagr.am media preview extension for Safari & Chrome.
Just like the title says. I use it daily, so I'd love to see it integrated with instagram