NetVibes . . . is one of the most popular web reader, offering a Google Reader-like interface as well as a snazzy iGoogle-like homepage.
NewsBlur is also a great option, with an interface that's very similar to Google Reader . . .
Feedly is popular, but definitely different than Google Reader. . . .
Update: A lot of you have mentioned The Old Reader as a great alternative
Google Reader Being Shut Down
Google announced on its blog yesterday that it will be shutting down its popular RSS app, reader. Essentially, Reader has been put out of its misery after it was maimed by the various "updates" that it had been subjected to over recent years. For all you RSS junkies out there, LifeHacker has compiled some alternatives: