[drunken monkey]

the mazda is a considerably bigger car than both the civic and tiburon so if it's size you need then this is it, unless the ford mondeo is available in your market.
of the other two, i'd say it's down to what you want, hatchback or coupe.
the civic gets my vote if it's the newest model mainly because it is such a nice design. Too bad it's a dumbed down car from the last gen though (although the type-r is looking promising)
the tiburon is a very nice looking car, especially the newest facelift. engines are a bit lacking though, even the V6.