When my IE8 (32bit) has the Debug Bar add-on enabled, it prevents some sites from loading @font-face CSS. The fonts are defaulted to their fallback typeface. Disabling the Debug Bar add-on allows the @font-face font to load correctly. This particular site is over HTTPS.
My machine is windows 7, 64bit. My version of Debug Bar is 6.0.1.
For the time being, I have Debug Bar disabled, but hope others may shed light on this issue.