I wouldn't say gear is massively important when just starting, but it helps when conditions are harder. I did a good dozen weddings on a couple of d200 when I first started and the pics are jut as good. You do get heaps better ambient and warm lighting with low light bodies and lenses though, and it does change the image a fair bit.

Right now I use two nikon d3 bodies and the main lenses I bring to a wedding is 14-24, 24-70, 70-200, 200 f2, 50 f1.4. My second photographer always brings two bodies as well and we all use ff nikons.

I find that bringing too many lenses actually slows you down and you lose the moment, as cliched as it sounds. I also bring about three flashes and pocketwizards for remote lighting. Hope that helps.