We always like to see business plans. And this is what we think a good business plan will answer. We like to watch and play with demos, too (they don't have to be close to perfect ).
We generally like things for which we might be customers or ones where we might know the customers. Said more simply, we have limited ability to investigate and get smart about all opportunities, so while the portfolio is not the last word on where we will invest, its a good indication of what we like.
Best way to reach us, is e-mail or twitter. And we also like connecting with new companies on angel.co.