ccleaner, very very safe, tuneup utilities,advanced windows registry care, and registry booster 2 this ones the best i have used till date,speeds the system after defragging the registry
TuneUp 2008 does the job. JV16 powertools is good too.
CCleaner is not a registry cleaner for that matter. It is like tool to clear junk files in your system.. History Sweeper is a superb alternative to CCleaner.. albeit its not a freeware..