MacHeist's nanoBundle 2 offer is almost over, which means the really good apps are on the verge of being unlocked. Already available? Tales of Monkey Island, in both Mac and PC versions.
By the time you read this post, RapidWeaver should already be unlocked, and it should be very, very close to unlocking Tweetie at around 50 or 60k bundles sold. Once Rapidweaver is unlocked, that should be no problem. Note: this isn't just the Tweetie that's out now, but beta access (and a free upgrade) to Tweetie 2, with the features that were found on Tweetie 2 for iPhone.