I want to learn something new, I'm not aware what is most suitable for this kind of problem. I can do this the normal way with PHP or asp.net with a RDBMS, but then what's the fun in that.
If it was me - I'd go for the NodeJS and MongoDB... because I haven't got a chance to build anything meaningful in either as yet. And also because I think MongoDB's geo-spatial stuffs would be useful for your project.