The Dramiel is the fastest Frigate in EVE.
The Claw is the fastest of the Interceptor group, but a Dramiel running an MWD is faster because of its lower mass, since MWD speed boost is affected by ship mass.
Things that affect speed are
Here's a table with the calculated speeds (base ship speed, max fitted/rigged and MWD, each without skill bonus and finally with all skills at level V3):
Here are the results as CSV. They were calculated from a subset of the CCP database export with this Python script, using the speed formulas from the top speed calculation guide and the Aenigma formula for bonus stacking penalties. Some calculated speeds were cross-checked against Pyfa.
1 The speed bonuses from the Overdrive modules and Rigs are subject to severe stacking penalties, making it fairly useless to cram more than 2-3 of these in your ship in total. However for the purpose of finding the fastest ship it was assumed that all ships had their low slots full of Overdrive modules and their Rig slots full of Auxiliary Thrusters. This is not a sensible build to fly around in though.
2 These bonuses affect the velocity directly and therefore don't matter for a ship comparison. They were not taken into account here.
3 Due to neither implants nor Leadership/Gang bonuses being applied, this is not the fastest these ships can go.
I used to live in wormhole space and this was a common question for us as we would often have to move wormhole loot through low sec or high sec while we were at war. We're talking small size but high value loot. We decided that cov ops were generally the best ships to use to transport our loot due to their small sig radius, high agility, and ability to cloak. The method we used was jump through a gate, hit the warp button and hit the cloak immediately after. That leaves about a second window during which you can be locked, but with such a small sig radius nothing but the best skilled (both in game skills and good reactions from the pilot) sensor boosted interceptors will be able to lock a cov ops. Additionally, the fast align time decreases the possibility of an inty trying to manually pilot into you to decloak and/or bump you so they can get a lock.
What I found was that the align time of the Cheetah and the Helios were pretty similar, but the Cheetah had a slightly smaller sig radius, so I went with the Cheetah. The optimal setup seemed to be 1 x Inertia stabs in the low, 2 x Nanofiber in the low, 1 x covert ops cloak in the high, 1 x Small Low Friction Nozzle Joints in the rigs, and 1 x Small Polycarbon Engine Housing in the rigs. With my skills, that meant a 3.0s align time and a 51.1 sig radius. I didn't worry about tank or ECM burst since if I got locked, I was probably dead.
In practice, I took what I found and applied it to my probing Cheetah fit. This meant that I used Gravity Capacitor Rigs instead of the agility rigs with a trade off of .2s to my align time. I also fit a 1mn AB, 2 x webs, and 1 x Warp Disruptor in the mids, but that's not relevant to this specific question. What I can say, though, is that I never got caught by a gate camp when piloting that ship through gate camps. It may not be the perfect setup, but it always worked for me.
Best Answer
Orbital bombardment uses small guns, so there is no need to use large ships for this purpose. From the orbital bombardement dev blog:
Among the destroyers, only the Catalyst and the Coercer have 8 turrets, so those two seem to be best suited for the task (ignoring the difference between hybrid, projectile and laser turrets for orbital bombardement).