Right from the get-go, your header takes up a little over 50% of the load up screen!!!

Thats bad, really bad. The first thing I would do is minimize that image and make it take up less height. I'm not even going to try and switch to 800x600 resolution, I can only imagine how big it looks there. You can also minimize that "An Antique Gramophone Parlor for the 21st Century" slogan after you shrink the image.
Scrolling down your site, everything is BIG, the colors keep changing, your menu looks like its part of an advertisement, the bottom of your page has a very scruffy closing. So where do we being? Let start with the "Over 10 Hours..." section below the header. Why so big? I think you're whole site consists of <h1>'s and font size="5" 's. Minimize that text. When you mention phonograph recordings available here for download and order a custom cd, make them a link so that people can go to that section, makes it easy to navigate.
Speaking of navigation, lets talk about your menu. First of all, a menu needs to be extremely visible. I mentioned before, I thought the menu was part of an advertisement with those 3 yellow boxes. Also, menu's generally come right after your logo at the very top, you've placed it 3rd in line. I would move it up one. Its hard to follow the menu items, everything is so

, I dont know what it all means. Like what should I expect from a menu item called "Start with some Favourites". The menu titles below for downloads cd builder etc... are fine. I think one of the things that make it hard to follow, especially with the menu, is the constant background color shifts.
Again, a description of your site after that is too bulky. Minimize, minimize, minimize! The second last paragraph is also centered? Why?
The part below THAT, I think you already know what I'm going to say. Refer to my paragraph above!
Finally towards the bottom, MORE OPTIONS! Enter Records, Enter Midifiles etc.... These should be things all found in one, easy to read, organized menu. You have things scattered left right and center. And to add to my frustration, you say "Some of the page links below are no longer supported, but still available", why? If you have dead links on your site, remove them. Why would you want your user browsing through pages that you know dont exists anymore.
At the very bottom is a ring advertisement, which is fine. But dont close the page off with that. Make a footer and put something nice, like Copyright, All Rights Reserved, a contact email, whatever, just close off the page with something other than that ad.
So I'm check out the introduction page, and to my surprise, the header changes. You now have a new image at the top. At least this time, the menu is easier to read, there's only a home button!
The Browse the Collection page, is fine. Except if you type in a keyword to search and go to the results page, it has no link back to the previous page, only to the homepage. Dont make your user use the back button.
At the risk of repeating myself, I get the general feel of your site and I know what to expect from the other pages. So to you I say this. Work on your navigation, first and foremost. Your site has a lot of depth, it has a lot of pages, with sub-pages, with sub-sub-pages. So its easy for your user to get lost. Make sure they know where they are and how to get back. Keep things consistent! Your header images change, your menu on some pages is at the bottom, the layout is different on other pages. But I think your biggest issue, is the big issue. Everything on your site is big. Especially on the first page, which is the page that really reflects the site, its just too messy and catered to people with bad eye site. Work on the fonts and the layout for a start. The content is actually pretty cool and your site is definitely a unique one. So just work on the presentation and I think you'll be great! Minimize!
