I have come to the conclusion that the most reliable lenses are the professional grade lenses made by the camera manufacturer. I have replaced all of my third party lenses with Canon lenses in the "L" series, and they all focus accurately in all sorts of lighting and are sharp to boot. It took me 27 weddings to pay for it all, however :eek:.
Not sure what the Nikon equivalents are (Nikon's naming conventions confuse the he!! out of me), but I could probably shoot an entire wedding with the 17-55 f2.8 DX and the 70-200 f2.8VR. I'd probably also add a 35 f2 at some point (because I like the focal length so much on a CF body) and an 85 f1.4. A 10.5 DX fisheye would complete the kit, along with an SB800.
And had the D70 not been $300 more than the Digital Rebel when I first started out, that would probably be what my kit would look like today (mounted on a D200, with a D70 as a backup).
Having said all of that, I shot 10 or so weddings before I started to have enough money to upgrade, and made due with high quality third party optics (like that Tamron 28-75). OK, to be honest, my first three weddings were with the kit lens, the 50 f1.8, and the dreadful Sigma 55-200. It wasn't until my fourth wedding that I bought the Tamron. I had a LOT more OOF shots that I had to throw away, but I was always able to deliver a product that my clients were happy with (especially at my dollar store price level). I always recommend that you buy the best glass you can afford now, and upgrade as you can afford to. If that's third party or slower OEM, than make that work for you. It's the photographer that makes the photo, not the gear! Let's not let Mastercard have too much of our money!