If it were the previous generation of these cars, I would say the Civic, because it was the most interesting of the trio. But the Civic has become more boring in its present iteration. It has ditched the double wishbone front suspension in favour of more common MacPherson struts. Nothing wrong with that, many high end cars have MacPherson struts, but what it means is that at least one way in which the Civic differentiated itself is no longer the case. From what I understand, it has lost some sharpness in the steering and handling.
However, will you, or your wife really notice that? It takes a real enthusiast to really care about something so apparantly meaningless as the type of front suspension.
If I were to buy one of these brand new, I would go for the Corolla. Yes, it is boring, but probably the best. Like has been said, the Protege is being replaced shortly with a new platform to be shared with the next Focus and Volvo S40. I have high hopes for that car, because platform sharing of this nature yields economies of scale and allows engineering previously only available to more expensive cars to trickle down to less expensive cars. So expect the next Protege to offer the sportiness and flair of current Mazdas, a lot of the safety features of Volvos, and the advanced suspension setup of the Focus. It will be a winner. Hopefully it will help boost the new 6's slow sales, as that car deserves better than how it's performing in the market.
Regarding the Echo, it will be a way to get the new car for less money, but if you decide you want it well equiped, it will border on the prices of the other three, for a car that is less substantial and more tinny feeling. Not my cup of tea to be honest.
Now, I must throw this in. Personally, I would buy a VW
Golf for myself, basic GL
model with AC
and 5 speed would serve me well.
"it's kind of like an Airbus, it's an engineering marvel, but there's no sense of passion" -- J. Clarkson re: Coxster