My favorite....OK but not from "a kit". this first starship was inspired by the Millenium Falcon, and was the first junkbuild that I actually drew preliminary sketches of, before starting construction.
This was also the first time I used the "Velocity Amplifier" main drive, and attitude control engines. It was also the beginning of the "Focussed Translocator Reactor" primary power source.
The second, and equal favorite, also a junkbuild. Inspired by the original Battlestar Galactica, this model measures 49" long. shown here with a coffee mug, and a Twenty dollar bill, for size comparison. The second shot is with the AMT, TOS Enterprise (close, but just a bit smaller than scale).
The most recent would be the USS Kodiac NCC 6000, documented in the StarTrek Group build '09, thread in this forum.