I'd go with Orton. NO isn't looking as strong as they did last year and TB has a very solid secondary. Orton has been able to throw on everyone so far, and Revis isn't 100%. And, with as much as DEN is throwing, the altitude and fatigue will be a factor.
That is a very tough call. While it's true Orton will be throwing as lot against the Jets as they ease Knowshon Moreno back in against the league's #1 run D, Brees' matchup is far from horrendous and prior to the season this decision would have looked like a no-brainer. I would say stick with Brees and hope for a true breakout game, but you can't go wrong either way.
You gotta start Orton. He's proven to be a worthy FF starter. He throws close to 50 times a game, and without Reggie Bush or Pierre Thomas in, the Saints are a one dimensional team without great receivers. Start Orton this week, even against the Jets, you throw that many times, you're bound to get some points.