CCleaner is excellent, current version incorporates a secure file shredder that almost seems too fast. I use
http://www.winaso.com/ for registry optimising. Seems to work pretty well; can undo last optimise. Not true freeware, the trial version is limited to 10 repairs, so the first one might take a few goes. It also has general internet/browsing speed up tools. TZ connection booster (google finds it) is a standalone lightweight connection optimiser that works as well as most. On the pistop utility, which is a non-functional optimiser, you can see the junk registry entries and delete them in regedit if you're feeling brave. Uncharted waters, this! Winpatrol is an excellent security tool, that also can be easily configured to disable those nasty, annoying registration reminders that some trial programs use, as well as preventing the the alteration of system settings by many types of spyware.
http://www.winpatrol.com/