Any of the radios marked FRS or GMRS will work fine. If they have the "Privacy Code" feature you will not have to listen to any chatter from others on the same channel. The GMRS radios are a bit higher powered.
Motorola is a good brand. Like Bem1962 said, you get what you pay for.
Oh, FRS and GMRS are not a brand, that refers to the frequencies they are set to.