Gonchar is not in Coffey's class...not even close.
That said, Gonchar is still a #1. He's not nearly as awful in his own end as he was in Washington. This is not to say he's in the upper echelon, but he's top 15-20 in the league.
Letang is the future, and maybe pans out as the same type player. Not a Norris contender, but a solid #1. He's already better defensively at 21 than Gonchar was probably at 28.
And, you guys forgot the Kurri - Talbot comparison.