a colony of shelldwellers will keep you interested with some other tanganyikan action going up above. Also, if you aquascape your tank nicely, you'll find it'll extend your non-boredom days extensively.
Whatever you do, if you want to keep a fish that won't be boring soon, stay away from everyday fish like mollies or guppies or basic tetras because they're not special (unless of course you really find an interest in them).
Whatever you'll do I'm sure you'll choose the right stock