For my two console sticks I recently did, ones art was at 200dpi and printed on a $300 color printer at work, the other was at 300dpi printed at Kinkos.
I couldnt tell much of a difference up close and personal (of course, it wasnt the same graphic either).
So in my opinion, theres no reason to go above 300dpi, and if you arent going to be inches away from it, theres little reason to go above 200dpi, unless theres equal difficulty in scaling your image to 200 or 300.