The UltimateDefrag GUI is a joke... it's an oversimplification of how harddrives work, and in reality a more classical view is a lot less misleading.
true, however, than (on most harddrives) access speed is slower as you move from logical sector 0 to logical sector "the end of the drive" (my raptor goes from ~90MB/s to ~55MB/s). Which is a bit funny, considering most drives have multiple platters, and if a really-simple layout was used, you'd expect speed to drop, the start from max again as a new platter is used, etc.
Even if UD was a decent product, I wouldn't use it because of the GUI, and the infamous NTFS "optimization" trick they charged cash for. Oh, and I'm not that great a fan of product names including the word "ultimate"