I did get the rear bumper guard (about $35 at the dealer). It is easy to put on and helps prevent scratches.
The only other accessories involve the stereo. Had the base Toyota. Put in a Pioneer DEH-P4000UB, 4 channel amp, 4 Polk speakers, XM radio and a Bazooka subwoofer tube. It really sounds good! I am using a flash drive connected to the USB cable for all my downloaded CD's. Had never done that before but it sounds amazing.
SportLynn: I am in Tucson which can be about 5 to 10 degrees cooler than Mesa. But after 100 degrees it does not matter much. But you will enjoy Nov through March when it is 60 to 70 degrees!