Guess what? I've got a fever, and the only prescription is... More Twitter! If you feel the same, you should check out TweetCaster for Android. It's a robust Twitter client, and even its free, ad-supported version lets you add multiple Twitter accounts and work with each account separately.
For each account, TweetCaster shows five tabs: Your stream, any @replies you've received, direct messages, starred tweets ("favorites"), and lists.
That last feature, lists, is a bit confusing. For some reason, they're called "TweetCaster SmartLists", but when I actually tested the feature, I couldn't see how it's any different from Twitter's built-in lists. I added a new list called "Tech Bloggers" with some of the bloggers I follow, and it then showed up on my public Twitter profile (under Lists).
If anything, the lists feature was the least polished part in TweetCaster's lovely interface: When adding twelve people to a list, the screen kept blinking (becoming bright and then dimming) with each person that was added, and I got multiple connection errors.
Another small niggle is the use of the Back button (a common pitfall for many Android apps). When working with a certain Twitter profile, I would expect tapping Back would take me back to TweetCaster's main screen, where I can select profiles, follow trending topics, etc. Instead, tapping Back simply transported me out of the app.
Other than these minor issues, TweetCaster is fun to use. The interface is laid out sensibly; for example, when tapping a URL within a tweet, you can select whether to open it, copy it, or put it into your Instapaper queue (no Read It Later support, though). You also get four different themes to choose from (two dark, two light). All in all, a worthy, efficient Twitter client.