Michael,
The short answer is that you can — if you manage your fonts with a good utility like FAP. Understand that if you have a large collection of fonts, you don’t want to keep all of them activated simultaneously. It’s an unwieldy list that creates long scrolls, and it slows down your system.
What the pros do is organize fonts into sets, such as, say, a default set of favorites; fonts commonly used for each client; fonts used for specific jobs; calligraphic fonts; humanistic fonts; typewriter fonts; Art Nouveau fonts; etc. You then can activate those you need for the day’s session, and deactivate those you don’t.
And then you have access to all your fonts, conveniently organized, and without hitting Photoshop’s glass ceiling.
Neil
One way is to clean out your font caches. You can do that with various tools applications (which ones depend on which version of the OS you have) or with a font management application that does that. If you dont have any of those one simple thing is to open FontBook, deactivate all fonts. Then reactivate all fonts. Restart machine. Check again. If that doesn’t help, find one of the apps that deletes the font cache, like FontFinagler, Leopard Cache Cleaner (you cna get them for free at versiontracker.com). After deleting font cache always restart machine. Then check again.