Having said that - here is some input
First, I never have the sound on when I am surfing, so the music makes no matter to me. As a rule, I think if you have music there should be a clear option to turn it off.
Next, I accidently ended up in your guestbook - fun to read, but I think a clearly marked entry point would be good.
Your home button takes you to the landing page - probably should go to the welcome page instead..
Your about us page could use some other navigation other than just a back button - I always like to read the aboutus thing and then have a look around a site, so nav buttons here would be useful for that.
Had a quick look at your policy page, and noticed you mentioned your costume gallery and your guestbook - would be nice for these words to be text linked to those things/pages, again, making it easiest for your visitors to get around. Same comment on this page about adding navigation opportunites.
On the Special Purchases page, needs nav opportunities, too.
On the welcome page - I love looking at the pics inside the shop, but they are taking up a great deal of real estate on this page - How about a picture trails kind of moving gallery with nice clear pics of the inside of your shop, instead of individual pics? Like this one on my party site:
http://www.sebastopolparty.com/
As I read through some of these pages I realize that you offer quite a variety of products and services, which I didn't realize from the welcome page -
theatrical rentals, full service in this regard
themed party costuming, again, complete
costumes for rental - do you also sell them?
do you both rent and sell accessories?
more stuff too.
These are things that might be obvious to you as a person in the business but are not so obvious to me as a customer, so I would like to see what you have to offer more prominantly displayed.
I love having the list of costumes - but I think I might make a smaller font, so that more could be visible without scrolling..
The costume reference page- I clicked on a couple of the buttons and got a wierd request for login/password.thing - then a restricted access message?
Okay, well this is a long post... and just my opinion, too.
Overall I like the site Robyn. It has a great deal of information, great depth. I like alot of your hallowweenie themed gifs, they're fun.
In general I am not a fan of black backgrounds, but I think it may suit your product. But I like the brown/black combos alittle bettere than the grey/balck combos..
Some tweaking and you will be there..
Good Luck