I would go with Intrepid class. Max speed of 9.975, lots of firepower, cuts out all the extra junk on the Galaxy class models but still very capable of scientific missions, unlike the Defiant. Plus it has spiffy pivoting nacelles! The bio-neural circuitry upgrades over the duotronic circuits, the EMH and the durability also big pluses to me.
Great job in giving the Intrepid class it's due, it's also my choice. I however would like to see it with a cloaking device a bit more firepower
and a little extra warp speed, lets say to 9.985...