When you include the movies as well there are so many to choose from! I think I liked the Silver/Grey uniforms that first came about in First Contact. They also appeared in DS9 in the latter episodes too. Still look like a pair of fancy pajamas like the rest of them. The uniforms in Enterprise were more NASA-ish which I liked too but I did think that it made the crew look a little like they worked in a tyre and exhaust centre.