[Fyron]

Defragmentation is 99% useless. Disk read rates are so high these days that any effect of fragmentation in modern file systems is nullified. There are occasional uses for degramentation, such as a bizarre case of 90% fragmented drives, but for the most part, its a relic of a bygone age. Its especially useless to have a policy of defragmenting before installing new games or large programs...

Xrati:
Look at the total CPU Time for such processes; anything that has 0:00:05 CPU Time after 2 weeks of running (most such services) is not going to be bogging anything down, especially when its total memory usage is in the 100s of KBs. If you see unnecessary services that have significant amounts of CPU Time and/or Mem Usage, removing them can help (a little bit). I just think your time is better served cleaning the registry and such, than stopping services that use almost 0 resources in the big picture.