I think SVN with VisualSVN or Ankh will work. The real crux is changing the culture of the team to use source control. Which one is almost a secondary question until the team agrees to WHY they should use source control.
As for going for what your team needs it seems that almost any of the main source control systems will work for your team to get into the basics. As your team's get comfortable with using source control and needs more advanced functionality then I would consider shopping if the one you started with doesn't seem to fit for you.
Here's a nice tutorial on Source Control in general which may help your team get to the WHY they should use it. http://www.ericsink.com/scm/source%5Fcontrol.html
UPDATE BASED ON YOUR COMMENTS:
@Blake - I hope you don't mind me
saying so, but that is pretty narrow
minded point of view. But, no, :),
firing him isn't an option. He's a
specialist in his field (not
programming related field), and if we
really tried we probably wouldn't find
more than fifty of such caliber in the
world. We're not a typical programming
team, that we share work, collaborate
between ... and such - most of us work
alone each on our own. But, as I said
in my comment to @Outlaw - I'm just
trying to help him, by introducing him
a new point of view, from what he's
doing now.
No, not exactly. We're not a
programming firm, strictly speaking.
We're a specialized engineering firm,
with a lot of programming involved
(cfd). So we have a lot of people
here, of various profiles. But this is
not about colaborating between
programmers; this is more of helping
him, but in a way that I don't want to
patronize him. So I just want to
suggest an easier way of what he's
doing now.
This presents a much better picture to us. Many of us responding are coming at the angle of a development team.
In this case, I think your best bet is to demo Source Control to him. Perhaps on something you are doing. Keep the demo simple. Perhaps start with SVN and Tortoise. Tortoise uses windows Explorer to manage the repository. See if he is interested. If he is then point him to the tutorial I listed above as this just talks about the basics of Source Control. Then you could suggest reading the SVN's basics chapter (http://svnbook.red-bean.com/nightly/en/svn.basic.html).
If he's really hungry you could also show the integration with VS with VisualSVN or Ankh.
Perhaps he will bite on it and everyone will be the happier. :)
As an aside - A long term goal I would push for in the company even if they are engineers who program is to have a standard to use Source Control even IF it's just on their local machines.
Good Luck! :)