The same thing goes in football, but to a lesser extent. If we rule out all the prop bets, then you just need to pick a winner against the spread. Assuming a moron isn't playing 20 games a day (thus, letting the juice drown him), then going 4-1 should produce a great profit. I will admit, though, that I once new a guy that could lose money going 4-1. If that one loss was the last game of the day, then he'd let his winnings ride and lose it all, plus the juice. Bad money management.
I know, I got off the subject here. You were talking about picking winners, not about accounting. In fotball, a guy will almost always come out a winner if he takes every single underdog on the card. Last season was an exception, as Vegas reported that the favorites came in a lot more than usual. (I have no #'s to back this up). Most people gravitate toward the favorite, as they are usually the better team. Vegas knows this, and adjusts the line to keep 50% of the money on each side (not always, but on most games). So, I tend toward the dog. I just think there's more value on the dog. I will pick favorites (like OU -3.5 over NU this Saturday), but I usually pick dogs about 70% of the time.
Mike, dude, what did I do to you?