Opinions requested on localization strategy

All,
Our application will require initially English and Spanish user
interfaces. There may be little or no database data that must be
translated, but that is a bit up in the air. The UI instructional text
as well as error messages will definately require translation.

I have looked at the gettext article, the new globalization plugin, and
the localization plugin. Each appears to have some strengths /
weaknesses. Since this is critical to the app and any strategy has
potentially far-reaching concequences, I’m looking for input from those
who have tried any/all of these solutions.

Anyone using these approaches? Pros/cons/gotchas? Any other approaches I
might need to consider?

TIA,
Keith