Here is the list of the companies that I use. It doesn't mean you have to use them, but these are the best of the best in the industry (according to me, of course):
High End Albums: Folio Albums
Fine Art Prints & Boxes: Folio Albums
Framed Prints: Kaleidoscope
They of course may not be right for everyone, whether based on style or price point. What's important when choosing a supplier you are going to work with is making sure they have your back, someone who is almost like a partner in your business.
So once you have your shortlist, ask around, what's their customer service is like? What's their quality control is like? There's nothing worse than an order arriving with a problem or an imperfection, and you then wasting your time trying to sort it out (oh the stories I could tell!).
In that respect, cheaper is not always better if I know half the time I'll be wasting my valuable time asking for reprints and replacements - I'd rather pay someone who will care enough to get it right the first time.
Other suppliers I know people are generally happy with:
The Print Space
Other popular suppliers (though in my experience they tend to have quality control issues - they will replace anything that's not printed right but they don't always bother checking before sending things out as they are very high volume): Loxley Colour and Sim 2000.