I use some of those registry tweaks but several listed are available options that are tweakable without going into the registry. My suggestion for good optimization for a casual user is to right click on My Computer in Explorer, select Properties, select the Advanced tab, click on Settings under the Performance section, and select "Adjust for best performance".
I would never run a registry tweak script unless I created it myself and I'd recommend anyone who uses such scripts to thoroughly investigate exactly what they are tweaking. Many tweaks are also dependent upon what your system specs are, how much memory you have available. If you have tons of memory, some of those tweaks are useless or of negligible benefit.
Edit: Also, one of the most common problems I see with casual users is they have lots of programs starting up when windows boots up. This happens because they install programs which then all want to put some nifty little icon in the task bar. Using msconfig to reduce the number of programs starting up when windows starts is also very helpful. I only have 4 programs that start with windows: ctfmon for languages (I use English and Spanish on my computer), my firewall, my antivirus and ultramon for my dual monitor setup. My computer starts up in about 35 - 40 seconds.
