is there a SP function that returns a valid title string for item? For example, I get an error for 0x07 (bullet) character, and from time to time I discover some new character that is not valid. I'm programatically setting title. So, which characters are valid and which invalid for item's title?
While there is a ton of guidance out there on the invalid characters topic around SharePoint, I have never seen any that speaks specifically to list item titles. It's mostly related to site, doclib/list, folder, and file names to make sure you don't run into any problems with URLs...here's KB article from Msft on the subject: http://support.microsoft.com/default.aspx?scid=kb;en-us;905231
I think from human-readability and co-existance with 3rd party solution standpoints I would myself restrict the title to alpha-numeric characters, but you're probably OK following the guidance on filename. in the referenced KB.
Hope that helps.