The Miranda type looks more like a late model Excelsior based ship, with the exception of the nacelles. Not that it's a bad thing. I'd say that one just seems to fit more along the those lines.
The fighter is neat, and I like that you didn't make it look like something derived from earth's contemporary aircraft.
The shuttle. It's neat, but I'd give it a non-earth design history. But hell man, that's one mother of an impulse engine! Fast as hell looking!!!
Oh- and the Titan Enterprise is simply fantastic. Well done!