I require managed. I've noticed VPS's are too competitively priced to not get out of shared hosting so I'm jumping ship and will stick with managed at first. I'll probably also get a cheap unmanaged plan to learn on until I get up to speed. I've see some tutorials available on WHT.
Not to stray too much off topic, but I've always run with CPanel/WHM on a shared reseller account. Regardless of whether people are running managed or unmanaged - for those of you that "require" an interface (like me), what do you think of the available free options such as DirectAdmin or lxadmin? Preferred distro?
Since I will have no other users I'm not afraid of learning another panel in favor of dropping CPanel to save server resources and license $$ every month - as long as it gets the job done.
Seriously, go with DirectAdmin... it is so much easier for everything. People who bash it, haven't used it. Their custombuild tool makes everything super easy.
As for the OS, go with CentOS, it's about as stable as you'll get and everything works on it.
If you need any help, let me know.