What are you interested in? What are you good at? Are you looking to lead a team to do this or develop things on your own? There are many questions you have not answered that we need to help guide our responses.
It's for all the kids demanding we do their thinking for them and create their "final year project idea".
For myself I know what I want when I get home from the office, and that's a nice evening with a good book or talking to old friends :)
when you think about a project first you should know i which lang you are thorough at and waht is easy to do. When i did the programe i was blind about the both and thus i suffered a lot. I did my programe in PHP but when i was doing that i was not empty in PHP. I had faced a lot only because of that