Ahhh fantastic discussion.
Basically...the ship speeds will remain the same. I'm taking a nod from Wing Commander where ships speeds barely changed over 5 games but the weapon abilities and whatnot more than compensated.
My favorite Terran ships in terms of looks were the Perseus, Artemis, and the Hercules Mark 2. I think its safe to say that those and some of the other examples I will be providing in an internal document will give a good idea of what the Terran ships should look for. They are still very Terran, but they have the smoother, more curved, futuristic look. And its not really a future look anymore either, take one look at the new SUV's or sports cars and you really see some nice lines. So thats the idea of the new Terran ships. Texture wise, the metalic colors like grey and whatnot. I wouldn't mind seeing what Thunder suggested which was a little Shivan influence (some small teal blue glowy bits on the ships somewhere - a bastardization of Shivan tech anyways). Most of the Shivan stuff is just reverse engineered anyways.
I want Vasudan ships (again outlined in better detail in an internal document) to continue the organic trend. I think I want the textures to take a nod from the Tauret...although I'm certainly open to suggestions too.
Shivan wise, what Thunder said is good. I'd like to shy away from perfectly black...but dull and dark greys are good. Hopefully with the source code we can really make them glow properly too and give that really harsh red on dull grey look. And spikes

Codedog...feel free to draw...but you'll get a way better idea of what to draw when I get you a copy of the internal doc. Which I will ASAP for sure. I've got ship names, abilities, and descriptions all out there for you to work off.