CurrentlyTrending.com $100 perhaps, so many websites hooking into twitter etc. Most people are going to just look on twitter. Type in "tw" its likely twitter will popup as a suggestion... typing in "currentlytrending.com" is just too long... No one will search Google to find out. I agree that "nowtrending" is better, ever so slightly.
AudienceReady.com $50 perhaps, has no value
So $150 for both, probably more if you are lucky, its more likely not to fetch much above the registration price. I have to admit I was slightly more enthusiastic over the name of the first domain to begin with, but when you apply logic to the equation, the novelty wears off.