I think the best uses of IT is for anything besides levitation.
Tyler brings up PK touches. Morgan Strebbler has a bunch of PK touches that use ITRs.
Animations are related in some ways to levitation but they are much more subtle. To have an object move across a table or under a glass can be beautiful. Haunted magic, like haunted decks and PK magic work well (Justin Miller has some great work on this type of effect. Most of his uses some sort of a loop set up). Daniel Garcia has a beautiful effect called "Life" that causes a paper butterfly to move subtly.
He doesn't use an ITR but Jeff Mcbride makes use of IT in a juggling type effect with paper butterflies and a fan.
Dai Vernon created an alternative to the linking rings using IT and 2 completely normal rings. This has been updated and used for all sorts of other links (rubber bands, coat hangers, keys etc.). In fact Alan Rorison uses reels in much of his most visual magic, ITRs may be too fragile though. Talking about penetrations, look into the silk through microphone stand, its a beautiful piece of magic with a clever use of a reel.