A little history of how seeds have done:
2003: Top 5 seeds all made the QFs. Seven of the eight seeds made the QFs; #8 seed was beaten in the round of 16. Upsets mostly happened between seeds in the QFs, as 1,5,6,7 were the four semifinalists.
2004: #5 Duke was upset 4-3 by Clemson in the regional final (presumably at Durham). The four semifinalists were 1-2-3-4 seeds.
2005: Top 5 made the round of 16. You can get good links to the regional results
here, but the draw link there is stale.
2006: Same links problem
here. Regional results show that the top 5 made the round of 16.
2007: Top 5 made the round of 16. Semifinalists were 1-3-4-10, as #10 Illinois upset #2 Ohio State in the QFs.
2008: Same links problem
here. Top 5 made the QFs. 1-3-4-7 made the semis, with #7 Texas beating #2 Ohio State in the QFs.
2009: Top 5 made round of 16. #5 Tennessee was upset by Texas in the round of 16; the other four won.
2010: Top 5 made the round of 16. Then #3 Texas was upset by Oklahoma, while the other four won.
2011: Top 5 seeds made round of 16.
Looks like one top 5 team in a decade failed to make the final 16: #5 Duke in 2004.
I will edit this in a while. Tired of waiting for a page to load at the horrible NCAA web site, which is also a treasure trove of stale links and results pages that have no seed numbers.