Whatever you do don't shoot 30p. 29.97 is also known as "1080/60i". Not to be confused with 1080/30p...which is very hard to convert to 24p, PAL or anything besides 60i. 24p is probably the most universal stock footage format to shoot on as it's easily convertable to NTSC, PAL and film.
For whatever reason 30p seems to be all the rage right now but it is not a standard format. Blu Ray doesn't support it and again converting it to international formats will hurt potential sales.
P.S. 720p is not 720x480 and 1080i is not progressive (1280x720p).