This app does not require you to login to a twitter account. It just fetches public tweets from users, searches and lists and lets you read them.
Once you specified the feeds that you are interested in, reading tweets has never been more efficient or easier. Quickly navigate from one feed to another with a simple swipe gesture and read twice as many tweets as with other twitter clients.

Update 1.1: Some bug fixes and context menu on press & hold on tweets.
Update 1.2: Slight performance improvements.
Update 1.3: Runs much smoother now and shows most recent tweet of selected column on live tile (refreshes every 30mins in the background and does not require the app to run).

Download and install the trial for free in the Zune Marketplace. The trial version does not allow you to manually refresh the feeds after the app was started. Setting up feeds as columns is also not supported in the trial.