At last year's opening keynote during WWDC 2012, Apple introduced a refreshed line of Macs, so it would make sense for the company to do the same this year, and it seems that's exactly what's going to happen. According to a set of leaked SKUs, Apple has plans to refresh at least one of its MacBook lines with new models.
9to5Mac said they received a set of new SKUs that are most likely new MacBook Pro models. The first set includes SKUs MD711LL/A, MD712LL/A, MD760LL/A, and MD761LL/A. These SKUs are most likely associated with either the MacBook Air line or the MacBook Pro with Retina display, as each of these lines have two screen sizes with two different hardware configs.
The second set of SKUs are ME177LL/A, ME182LL/A, and ME918LL/A. No one's really sure what these SKUs are for, but it's likely a specific a screen size of a particular MacBook model will see a refresh, but we're not sure if that's case, as it would strange for Apple to focus only on a particular screen size for a refresh.
As far as what else we'll see at WWDC this year, new Mac Pros could be on the menu, and it could be the first time in a few years that we'll see a significant update to the tower computers. iOS 7 may also be unveiled, complete with a Jony Ive-designed user interface that will sport a flatter, minimalistic look and feel.
At this point, it could be anyone's guess as to what exactly Apple will unveil next week. On top of a possible Mac Pro refresh, we've heard a full MacBook refresh is possible, as well as specifically new MacBook Airs to come our way next week. Furthermore, we'd be a bit shocked if Apple didn't give a boost to their MacBook Pro Retina lineup, and with Haswell launching this week, we could easily see the new chips make their way into MacBooks and Mac Pros next week.