Bulow is a great venue, that we toured when planning our wedding. Just be sure to time your wedding so that the water is in. Something I never thought about. Other wise you have a swamp smell sometimes. We had our's at the Magnolia Plantation. It was wonderful and we had 3 options to choose from. Our coordinator, Wendi Mullis, was great about helping us choose the right place and time. Check out wwww.MagnoliaPlantation.com
Charleston is a wonderful place for a destination wedding. I own a travel company(we do lots of destination weddings)and planned an absolutely beautiful wedding there this past fall at the William Aiken House. You can check out photos on our Facebook page for the Jones/Gladden wedding. We also work with a local wedding planner in Charleston who does a great job. Let me know if you need any more specific info.
I've heard a lot of good things about the Pavilion at Pepper Plantation, too.
Do you have a photographer yet? You should check out Christa Harder (www.christaharder.com). Her work is phenomenal, her packages are very reasonable, and she travels anywhere in NC, SC and GA for free.
Several places are wonderful
Seabrook Island (they have a nice patio right on the ocean)
Click on each tool to see a sample.