WhoIsNext is a utility application developed for Android mobiles, which will help you to find out to whom you want to call next.
Call History or Call Log won't be useful for this purpose. This application uses the LAST_TIME_CONTACTED information and sort the list of contacts based on that info.
So you can keep in touch with those (Friends or relatives) whom you haven't called recently. This application is not using your contacts for any other purpose. For more details please visit my blog post.
Try it now! It is available for Rs. 0/-