Well, you already know my personal favourite.
There is one very important matter to keep in mind here: a control panel can never be a substitute for having a solid understanding on how the underlying parts actually work. One way or the other, you are going to need such a level of expertise.
It won't make things easier, only easier to manage. The real strength of a control panel comes as soon as you're hosting several individual websites and related services (such as e-mail, optional back-end database, specific e-mail filtering settings, etc.). Because if you need to move such a website from one server to the other then it can become quite tedious to do so; you need to copy the physical data itself, the configuration of the web server as well as the mail server, you'll need to make a dump of the database as well as making sure to copy the associated credentials and that's ignoring everything else.
That's where control panels can shine. Last months I've been very busy with a full migration from Linux CentOS to FreeBSD and if it wasn't for Webmin / Virtualmin it would have taken me a lot more time than it has now. Simply because I can treat a website as a single "product". And that product includes everything for that particular customer (e-mail settings, database, etc.).
But as said; you'd still need to understand why open relays are bad when dealing with a mail server, you'd still need to make sure that whatever permissions you're applying are actually safe, you might need to know how to utilize Apache's suexec routines (how and why).
Most importantly of them all, in my opinion of course, is that you should be very weary not to become too depending on such an admin panel. I've seen that happening just too many times, and it's a poor sight indeed; people knowing what options to click in a panel like Plesk or cPanel, but without having the slightest idea what it is they're actually doing.
It'll work, you will most certainly be able to get some work done. But you're horribly limiting yourself. Now your limits aren't so much the options which the software you intend to use (mail server, web server, etc.) can provide. Instead your limitations have now become that which the developers behind said admin panels actually understand about the underlying products.
And it's my experience that this level of understanding isn't always as great as it could be. In my opinion that's definitely something to keep in mind...
