The only in season value in being ranked high in the preseason or early portion of the season is that a few losses here and there don't hurt your seeding as much as a loss to a team that is ranked lower.
Being ranked in the preseason is also nice because it shows that a team has earned respect, and a reputation, and a coach can tell a recruit "you see, we've been Sweet 16 two years in a row, and now we're top 5 heading into this season, but we could really use a man like you to help get us into the final four..blah blah blah." It also earns you much needed publicity.
Other than that there is little value in being ranked highly in the preseason. Sure, you might say that #1 seeds are much of the time highly ranked in preseason polls, but that is because they are great basketball teams, not because of any preseason ranking.
In 2009 the preseason top ten included was 1. KU, 2. Mich. St., 3. Texas, 4. UK, 5. Nova, 6. UNC, 7. Purdue, 8. WVU, 9. Duke, 10. Tenn and Butler was #11. Can someone please tell me the valuable role, other than what I described earlier, that being ranked highly in the preseason played for these teams? Because, I don't see it.