A VDS can definitely be too complicated for beginners, especially if they pick the wrong one. The secret to finding a VPS which can be most easily used by a less-than-expert customer is to get one with a good control panel. Control panel software allows the owner of a server to partition the server into separate accounts and domains, and to make management of common tasks more easy. It might seem strange that a person would leave a shared hosting account, get their own Virtual server, and then install shared hosting software on it, but the payoff is in the fact that this will insulate the administrator from many of the mundane and arcane details of server administration. Oh, and the only sites fighting each other for the resources on your server will be yours.
There are several popular brands of control panel software on the market. The most common ones (in the North American market) are CPanel, Plesk, DirectAdmin and Webmin. I've used all of them and would personally recommend DirectAdmin, which is easy to use, powerful, and has small memory demands. CPanel is very popular, but some users complain about its size and security. Another drawback to some of the control panel software is that sometimes it will set itself up so that manual configuration of your server from a shell prompt becomes difficult or impossible. DirectAdmin and Webmin have a reputation for working with, but not monopolizing your server.
One last consumer tip for customers who would like the added ease-of-use that a control panel brings. It is much more expensive to get your Virtual server and control panel separately. This is because control panel vendors heavily discount their software when selling to hosting companies. They, in turn, will offer it to their users at a price far less than the retail price offered by the manufacturer. To minimize the effect on your wallet, sign up for a VPS with the control panel included.