Change front brake and rotors - seems pretty extreme, unless you notice some brake pedal pulsations and decreased braking performance. With the OEM setup - hard to wear both the rotors and pads out at the same time (pads usually go first).
Sepentine belt - you could do it yourself. Takes about 10-15 minutes tops, if your familar under the hood - about double that if you are not.
Belt runs about $30-$35, put a wrench on belt tensioner, pull it back, slip old belt off, slip new one in its place, release belt tensioner, done. This assumes that the belt is bad in the first place - varys from car to car do to driving conditions and environmental differences. I've seen belts last from a short side of 15K to as much as 100K. Just look at the bottom of the belt, where there are longitudinal ribs - if there are any missing chunks or excessive cracking, signs of glazing or burned spots - then replace the belt. Lots of little cracks are normal.
Cabin air filter - recommend changes at 15K, but also, depends on driving conditions and environment. Can't really be cleaned out - beign a pleated paper element - but you can at least knock off the big stuff. Again a good DIY project - with a Philips headed screwdriver - takes one about 15 minutes, tops, to remove the glove compartment bin, replace filter and button everything back up. This has been discussed in great length in this forum. If you have already replaced it at 30K - might still be OK. I have pretty bad allergies, so I need to make sure I change it often - but the filter seems to last about 30K for me.
As for service - what needs to be done. You should really use the dealership's schedule as a guide - doesn't mean that refusing one item or another will automatically mean dire news for your car. If they pressure you - switch dealerships. All that needs to be done for proper operation is detailed in the factory service schedule (can be found online on the Toyota website, link here: http://smg.toyotapartsandservice.com/owners.php)
Everything else is just extra work, mainly to add to the dealers bottom line. From what you listed - I would say do the serpentine belt and cain air filter yourself (if they need to be changed). Brake service - that might be neccessary - depends on how you drive the car. But if you drive quite conservatively and the brakes seems to be fine - replacing both pads and rotors together, does seem like excessive amount of work. If the pads do need to be changed do to being completely worn out - then I would also replace the rotors. Used to be that you could "turn" down rotors on a lathe - not anymore. Newer rotors are much thinner and don't have as much extra "meat" on them to turn down. Check around at different dealerships or good independant garages - you should be able to find a better deal than that.
Good luck.