Obviously, I'm not a wedding videographer, professionally, but I want in on the conversation! :)
I'd say depending on the cost, HD is attractive. Back when a plasma cost $16,000, it was a definite no for me. But now that you can get good ones for $3,000, absolutely. HD is, as mentioned, just a matter of time and agreeing on standards. I'd be willing to pay 50% more for HD, and I think that more and more consumers will opt for HD as prices come down.
Also, I think it speaks volumes of you as a professional to even offer the option of HD. Instant credibility in my mind. I was at a one-camera wedding this winter, and that shocked me.