IMO, 1 word names that aren't entirely obscure may prove to be a decent investment if you truly believe in the .mobi extension (eg. recreate.com would be worth a fair bit). There aren't really any buyers for names like this at present, and you can't really apply any kind of "percentage" of what the .com would go for to such names.
Worth the regfee at present? No.
Worth 5x regfee five years from now? Maybe. Maybe alot more.
All the best with whatever you decide