illegal characters and not-so-illegal characters

A filename cannot contain any of the following characters:
\ / : * ? " < > |

...


Characters that are valid for naming files, folders, or shortcuts include any combination of letters (A-Z) and numbers (0-9), plus the following special characters:

^   Accent circumflex (caret)
&   Ampersand
'   Apostrophe (single quotation mark)
@   At sign
{   Brace left
}   Brace right
[   Bracket opening
]   Bracket closing
,   Comma
$   Dollar sign
=   Equal sign
!   Exclamation point
-   Hyphen
#   Number sign
(   Parenthesis opening
)   Parenthesis closing
%   Percent
.   Period
+   Plus
~   Tilde
_   Underscore

full article at serverfault