The maximum number of New England Patriots games that Fox can broadcast in a year (excluding the preseason and Super Bowl) is two, so it would be somewhat unusual for them to pass on the opportunity to air a Pats game. That being said, when the Bucs are in Foxborough (a) it's an early game and (b) CBS has the doubleheader that week. Fox has six early games that day so those games are likely to be split fairly evenly regionally.
The week six game against New Orleans on the other hand will be shown virtually everywhere, and will get their top broadcast crew (Buck and Aikman). If things go as planned then that will be the game that Tom Brady ties or breaks (I forget which) Brees' NFL record for consecutive games with a touchdown pass, on top of featuring two of the NFL's best offenses. There are only four areas that won't get that game: Arizona is at SF on Fox at the same time, plus Seattle and Denver have home games at the same time.
For what it's worth here is a list of the broadcast teams on Fox and CBS. You can get an idea of how big a game is depending on the broadcast team. I consider the Patriots games consistently getting Nantz/Simms, Gumbel/Dierdorf or Buck/Aikman to be a sign of respect.
CBS
1) Jim Nantz//Phil Simms
2) Greg Gumbel//Dan Dierdorf
3) Ian Eagle//Dan Fouts
4) Marv Albert//Rich Gannon
5) Kevin Harlan//Solomon Wilcots
6) Bill Macatee//Steve Tasker
7) Spero Dedes//Steve Beuerlein
Fox
1) Joe Buck, Troy Aikman & Pam Oliver
2) Kenny Albert, Daryl Johnston, Tony Siragusa
3) Thom Brennaman, Brian Billick & Laura Okmin
4) Kevin Burkhardt, John Lynch & Erin Andrews
5) Chris Myers, Tim Ryan & Jennifer Hale
6) **** Stockton, Ronde Barber & Kris Budden
7) Sam Rosen, Heath Evans & Molly McGrath