There are several good places. South Mountain, Hawes trail, Usery pass, Mc Dowell, Pima and Dynamite, estrella, white tanks, Goat trail (??), Black Canyon trail, Cave buttes recreational area. Depends on what you like.
Mormon-national is a great downhill. Hawes is dome good trail riding. Mcdowell Mountain park has good XC tracks. Pima and Dynamite if spectacular trail/XC but is sandy near the normal entrance (requires a state land permit)