The NYTimes did an interesting spread on "extreme beers," versions of European beers that Americans have supped up. These are things like "Double IPA" or "Hop Wallop." Some brewers and beer critics did a taste test and you can read all about their results.
The beers tested:
Dogfish Head 90 Minute
Lagunitas Maximus IPA
Oskar Beers - Gordon Beer
Southern Tier - Un-earthly
Weyerbacher - Double Simcoe IPA
There are some other great multimedia links on this page to Belgian brews, Porters and other browns.