Warning! Though most travel in Ecuador is relatively safe, economic instability provoking unrest in the country's recent past does warrant that extra bit of caution from the traveler. Since the national state of emergency declared in January 2001 - in the wake of a popular uprising inspired by the Council of Indigenous Nations of Ecuador (CONAIE) and the resignation of ex-president Jamil Mahaud - the security situation has been shaky. The aftermath saw riot police and protesters going to battle, general strikes, road blockades and even bombings. That said, things have settled down of late, and street crime - usually of a non-violent nature - in Quito and Guayaquil remains the most common hazard to those on the tourist trail.
Travel to the northeastern regions, particularly Sucumbios and Orellana provinces, is not advised. If you really must be in the Colombia-Ecuador border areas (again, not advised), exercise sense and caution. Oh, and it's a good idea to steer clear of mass demonstrations, as these often have potential to unleash all sorts of nasties, from both protesters and police. Most importantly, just stay aware of what's going on locally and in the world.