Read [link|http://www.amazon.com/exec/obidos/tg/detail/-/0738204633/002-8952320-5849624?v=glance|Winning at New Products] to learn how the process of project choice and definition should go.
This is depressing because you will have trouble finding an employer who does even a marginal job at it, and the main failings are in marketing, not technology.
(Disclaimer: I am only about half-way through. My belief that the advice is good is based on its making sense, the fact that he makes it clear what evidence his theories are based on, and the fact that when I borrowed this, I was told that it is a classic in its field.)
Cheers,
Ben
PS a good review can be found at [link|http://www.pdma.org/bookstore/books/winningatnewproducts3rd_review.html|http://www.pdma.org/...ts3rd_review.html]