Well ... many will disgree but heres my personal opinion:
(Which is really what this subject ultimately comes down to)
I find it better off staying with Norton IS.
I do not see the benefit of 360 myself. NIS 2011 itself is excellent however.
But the rest, theres better options out there, many of which are free.
For backups, Acronis.
However, there are also a couple free alternatives that work just as well for many.
Macrium for example.
For cleanup and maintenience, again free applications.
Between whats already included with Windows + Ccleaner.
Cleaning up temporyary junk, defragmernting and managing startup items are the main things to keep your system running well.
You do not really need anything special to do this though.
Managing startup items etc is actually quite simple. It can even be done through Ccleaner if you so choose.
Everything else Windows can do itself.