Performance and operation
Except for ccleaner, which automates some tasks that can be executed through a batch file, I see little value in these utilities. I use contig.exe in a batch file to defragment some files that get constant read/writes by their applications (e.g. outlook databases, guildwars, indexing databases for WDS, Google Earth), use the "defrag c: /b" on XP to defrag the pre-fetch data routinely, and keep the web browser cache to 64 MB.
Something is definitely wrong with the test machine. I haven't experienced this level of poor performance on less impressive systems running the same OS (how about a 1.8 gHz Sempron with 1GB RAM?). I don't disable services, like indexing. In my experience, disabling some Windows built-in services slows down the computer. However the default settings on Windows Vista for VSS and Defender are definitely a problem; this seems to be addressed for Windows 7.
My Golden Rule for good computer performance is to aim for a steady state system, as much as possible. I install a stack of carefully selected software, and try to not alter anything after that, except for patches and updates. The xBox360 runs Windows. Does it ever crash? Maybe it does, but not very often. Everything runs inside an hypervisor, and as such things don't change much.