The Focus is a good car that has had reliability problems - Car and Driver has liked it for several years. Maybe Ford has resolved the quality issues by now.
The Corolla is a good car. The 03 and 04 have a nice upright seating position and is pretty comfortable in the back. A friend has one, but I've never driven one myself.
The Honda Civic is a good car. The newer ones seem very plain to me, but mechanically the car should be top-notch.
The Civic and Corolla will probably drive differently. Civics usually are a little "sportier" than Corollas. You should drive each of them to see whether you have a preference. Either should be a very good choice. The Focus may be fine, and should be substantially cheaper, but unless things have changed recently you're taking more of a chance on the quality with the Ford.
[link|http://www.edmunds.com|http://www.edmunds.com] has lots of good information.
HTH.
Cheers,
Scott.