I've read PG's ideas [1] and Start Small, Stay Small [2] and I laughed my way through patio11's 'Hello Ladies' [3] ... BUT I'm still really struggling to find a niche that looks a) worthwhile b) addressable and c) not already saturated.
Any thoughts appreciated.
[1] http://paulgraham.com/ideas.html
[2] http://www.startupbook.net/
[3] http://akshat.posterous.com/patio11-says-hello-ladies