To filter out the total idiots, I ask people to give me a one-paragraph answer to one of 5 technical-ish questions. That lets me spend plenty of time on the people that do make it through. I try to reply to all applications personally within 24 hours. Interviews take scheduling priority over pretty much anything else. We meet right after interviewing someone and try to get them an answer either way within a day.
If folks have other things they like (or hate) about hiring processes, I'd love to hear about it. We really want to get this right.