gerberas, tulips, cala lily, red larkspur, dahlia, red hydreanga, carnation, lily, red iris, orchids, day lily, red verbena, pentas lancelotte, red velvet (Achillea millefolium) amaryllis ... what season are you marrying in?
gerbera's, dahlias, red velvet, etc do best in mixed bouquets unless you're an expert in binding bouquets. Lilies can stand by themselves or be mixed with other flowers, red velvet is a great filler, Amarillys a very special choice if you are marrying near winter. As to bridesmaids: a single red cala lilly can make a very dramatic statement if you go for sleek or elegant, modernish style. Tulips are great for a more fresh note. If you work with lilies, be very careful of the polen, make sure there are no threads left that can stain clothing!!
If you go for a romantic style, consider a tussy mussy: an elegant silver (or silver plated) small holder for flowers. It can contrast beautiful with red flowers, though it works with mostly everything.