I find the pop-ups abd the search box to be the least annoying to the user. But they probably won't provide enough revenue. Lets say a site has 30 hits per day, and a pop up goes on 30 times. About one user clicks on the pop-up, per day. That equtes to about 50 cents of revenue a day. Multiply that by 30 days and you have $15/month. Let's say you have 500 users, that's $7500. Erp... Perhaps it will work.
Remember, however, that warez users and abusers will suck up that bandwidth. Also, many sites get less than 30 hits, 30 hits is an extremely optimistic guess.