You know sometimes, it has partly to do with how photogs dress during a wedding. While there's a need for mobility to get angles, please at least dress decently and come in (minimum) a collared shirt, pants and dress shoes. I've seen too many wedding photogs in tee shirts, slacks, berms, slippers, etc. I think too often wedding photogs use the mobility reason to dress down and I think that's mainly why people are disdainful of them. If you actually bothered to dress properly, people would look at you in a whole new light, trust me.
Anyhow, OT aside, I think that the thread starter's set-up is pretty decent for weddings already. The 17-85 does yield some pretty sharp photos and it does have IS to boot so handshake is less of a problem. If you have serious handshake issues, remember the 1/f length rule for shutter speed and for you, leave the IS on! You may probably need to use the flash to facilitate this. If that still doesn't work, try using a tripod. If that still doesn't work, i'm pretty sure that there might be a problem with the equipment; send it in for servicing. If it comes back and you still can't get sharp photos, you need to train up your own skill