Is it acceptable to have a unique wedding invitation even if you are planning a traditional wedding? Absolutely. While some people like to coordinate their invitations with the style of their wedding, it is not strictly necessary. If you have a fun or different idea for your wedding invitations, then, by all means, choose the invitation that you want. If you plan on celebrating with a formal ceremony, make sure to mention that on the invitation, such as "black tie requested". On the other hand, if the wedding invitation is off_beat people may assume that your wedding will be a more casual affair unless you specifically state otherwise. Putting the information on the wedding invitation prevents any confusion.
This will vary a bit depending on whether parents are issuing the invitation or whether the couple are doing so but in general this style is acceptable: