Next Gen ran from when I was three until I was ten, and I never missed an episode. How could I not post the Enterprise-D?
Truth be told, the Galaxy-class actually looks pretty derpy without the show's careful hiding of this via camera angles. :/
Well, it's an aesthetic argument, so there's no proving it one way or the other, but I respectfully disagree. Having had the benefit of several video games allowing free-looking around the exterior of the ship, I think the ship's lines look elegant from any angle. As a car-affectionado, it always surprises me how many vehicles have such attention-to-detail paid to the front and sides, only for the back to look like an arbitrarily tacked-on chunk because the car couldn't get any longer. A lot more thought was clearly put into the Galaxy class, so that every section serves its function and fits into the aesthetic design. Now, some of the early concept art looked pretty derpy, but after numerous revisions, I think the final product looks good from any angle.
That does come with the caveat that the drive section looks pretty silly with the saucer separated. I know the function was intended from an early stage of the design process, but with the top of the drive section's neck standing in for a mini-saucer, the rest looks completely out of proportion.
Besides...
[Defiant]
I never really cared for the
Defiant class. It struck me as too much of a deviation from other Starfleet vessels and as a conceit within the context of DS9. Specifically, when the
Defiant first showed up, it felt like someone finally bowed to a committee that had decided that a show about space exploration didn't work with a fixed installation.
To me, if Starfleet was going to design a ship to fight the Borg, it would have come out a lot more like the
Sovereign than the
Defiant. For starters, the
Sovereign looks more like an evolution of Starfleet technology, while the
Defiant looks like it started completely from scratch. Beyond that, though, the
Sovereign class could clearly push deep into unknown territory, looking for Borg targets to attack, fulfilling both the need to deal with the Borg and Starfleet's exploration mandate. The
Defiant class, while combat capable, pretty clearly isn't meant to be away from support facilities for extended periods.
Also, in it's one fight against the Borg, the very beings it was designed to combat, the
Defiant was pretty soundly beaten. By comparison, the
Galaxy-class more than fulfilled its missions of diplomacy and scientific discovery and further stood in as a capable combat vessel in the initial confrontations with the Borg and later in the Dominion war.
Finally, ending on the aesthetic note on which we began, the
Defiant isn't very visually appealing. It's a disc with some dongly bits sticking out. The note I made about cars' back ends is in full-effect with the Defiant, as what lines do flow from front to back just arbitrarily terminate.