Mac/iOS: If you haven't settled on a Google Reader replacement yet, NewsBar offers a tempting option if you live inside the Apple ecosystem.
NewsBar comes in both Mac and iOS flavours, and both offer an attractive take on feed reading. The Mac version centres around a highly-customisable, translucent window on the side of your screen that updates with any new additions to your feeds. Clicking on any item creates a pop-out preview window, but you can click through again to open it in a browser. It's not particularly jaw-dropping, but it's a nice change of pace from a traditional windowed app like Reeder.
My favourite feature of the Mac version is the ability to create custom notifications. New articles won't trigger Mountain Lion notifications by default, but you can add any number of keywords to create a banner and audio notification to grab your attention. Unfortunately, the app lacks a few features you might be used to, notably the ability to send articles to read it later services, so this might be better suited for casual readers than voracious RSS hounds.
The iPhone version is visually distinct from its big brother, and doesn't offer the same level of customisation, but its flat interface is very attractive and readable in its own right. I did miss the glut of gestures and customizability I've seen in other iOS offerings, but if you mostly read RSS feeds on your desktop, the mobile version is a fine companion. It does have the unique advantage of syncing with the desktop version over iCloud, skipping the need for a dedicated service like Google Reader or Feedly. You can also add an OPML file containing all of your feeds from Google Reader via email, which is a powerful and much-appreciated touch.
NewsBar might not have every feature under the sun, but it's prepared for the coming Google Reader shutdown and offers enough to satisfy passive RSS consumers. If it seems like it might suit your needs, check it out on Apple's various App Stores.