9to5's "favourite Apple source" says that WWDC will bring "minor" updates to the MacBook and MacBook Pro lines. The source mentioned speed bumps and "3G hardware built-in." I don't know about you, but 3G hardware built-in seems like a pretty big deal to me. The source also speculated with non-removable batteries for other laptops than the MacBook Pro 17.
Their source is also pointing at Final Cut Pro, Aperture, Logic, and Shake updates, but WWDC seems like a strange venue to announce these. Specially since—for past releases—these applications were announced separately, along with lower key niche industry events. [9to5]