Mid-Late "Deep Space Nine" and "First Contact". Quite militaristic, in line with Starfleet's primary duty - to defend Federation. Early DS9-era uniforms are second, TOS uniforms being third, and 29th century Starfleet uniforms 4th. Section 31 uniforms are 5th (Section 31 is still part of Starfleet, and uniform is nice, but too much leather. If they wanted leather, they would better use jackets). Enterprise uniforms are close 6 th. Classic TNG era uniforms are worst ones, and Captain Picard seem to agree with me, althought for different reasons.
EDIT: Tos uniforms 2266 model.