Now that our friend at ark42 has decided to stop generating all that helpful pricing data, I have moved to MTG Goldfish ( http://www.mtggoldfish.com/ ). Here they are in alphabetical order, and including the three soon to be issued planeswalkers from Theros.
These prices are for the paper cards.
Here they are in increasing cost (poor Tibalt!). I have highlighted in green the planeswalkers that will be Standard Constructed legal once Theros is issued.