If you're looking for an inexpensive Mac, the Mac mini is your answer, and Apple just released an updated model today alongside the release of OS X Lion. The new model sports Intel Sandy Bridge processors, either in the Core i5 or i7 flavor, along with a Thunderbolt port, Lion pre-installed, AMD Radeon HD discreet graphics, and Bluetooth 4.0. One thing that disappears from the Mac mini, though, is the SuperDrive. Instead, you'll have to rely on things like the Mac App Store for installing apps, and this shouldn't be too big a deal. The Mac mini starts at $599, and there's also a server version that ships with Lion Server for $999, and that one packs a Core i7 processor. You can purchase the new Mac mini now from the Apple Store.
Apple also released a refreshed MacBook Air today as well.