svk looks promising, but personally, I don't think the documentation is there, yet. Whereas with subversion, there's the fantastic Subversion Book. Download, print, read and go. Perhaps somewhere down the line I'll feel that svk is worth a second look. The OP was looking for guidelines on future projects -- from a fresh start, I'd second taking a good hard look at subversion.

Regarding the migration challenge, the Subversion book includes an appendix on Subversion for CVS Users, which also discusses the latest tools for migrating a CVS directory to subversion.