Choose the hubs that you link to yourself, don't rely on the link suggestion tool to add some links. If you care about the readers of your hub then you should only link to high quality hubs. That means either your own hubs - at least you know the level of quality of those - or hubs of others that you've actually read.
Other than that, it does not really matter. Some suggest not to link too much to the hubs of others because you'd be giving away hard earned traffic. In some cases someone else has written it perfectly and it makes sense to link to them.
Linking to your own hubs is certainly beneficial because it increases views on your own hubs.