If you want the look of a traditional wedding invitation, but would like to implement your wedding colors, consider using one of your colors as the lining color for the envelopes. This is a subtle and attractive way to customize the appearance of your invitations. Other places to add accent colors are on envelope seals, monograms and motifs. Careful use of color can add drama or whimsy to your invitations without adding much to the price.
If you and your fiancé would prefer an oriental theme, you can choose to send intricate oriental invitations. If something more offbeat appeals to you both, send an anchor or pirate hat shaped invitation for a pirate themed wedding, or an old_world style invitation on parchment paper that looks like they have been hand written for a very traditionally themed wedding.