There are lots of professionals who tend to vote Republican who vote early, because they don't have much control of when they will be in or out of town. Even before early voting was legalized, my father used to frequently request absentee ballots, because he would often have to travel to Houston on business on short notice or go out in the field to monitor a well being drilled or logged.
Another advantage to early voting is that it can counteract the media's propaganda that is designed to discourage Republicans from voting. Remember the exit polling in 2000 and 2004 that was inaccurate but indicated Gore and Kerry would win? Several networks called Florida for Gore while people were still voting in the Florida panhandle. As a result thousands of people went home rather than stay in line and vote for Bush. If lots of Republicans vote early, they will be immune to those media tricks designed to suppress Republican turnout.
I forget about absentee ballets when talking early voting, and so does the media. They just report on who is coming to the polling sites. So far, it appears a lot of stories like the one from Texas in this thread.
Not good news for us.