I do prefer Bavarian Weizens to American Wheats. Weihenstephaner Hefeweissbier or Franziskaner Hefe-Weisse are two that are usually readily available in the states and very good if they have been handled properly by the distributor. Sierra Nevada's Kellerweiss is one of the best US attempts on a large scale. They use the same open fermentation techniques as traditional Bavarian breweries do that weizen yeast really like.
To begin, I have to cheat a little and say Lagunitas Little Sum' Sum'. They put a ton of American fruity hops in this particular wheat though. Man what a good beer.
As far as the more traditional wheat styles:
Hefeweizen - Paulaner Hefe-Weizen
Witbier - St. Bernardus Wit, Unibroue Blanche De Chambly, Allagash White, Hoegaarden White Ale, Ommegang Witte
Last but not least is my favorite wheat beer to date...Unibroue Chambly Noire. Beer Advocate classifies this as a Belgian Dark Ale, but it's really a dark wheat beer. In my opinion Chambly Noire is one of the most underrated beers I've come acrosse. It has a mediocre average of 83 on Beer Advocate. In my opinion this beer is a 99. All the characteristics of a solid wheat beer, with tons of that Belgian style malt and yeast character. Super complex. I could spend all day trying to describe all the flavor and nuances I pick up in this one. MUST try!
Nice...I visited the brewery on a road-trip to Fort Collins a few years ago. It was my favorite offering they had.
Long story short...bought an Easy Street Wheat T-shirt, wearing it as I type this.
I found that after taking a 3 month long BJCP study group with a grand master judge, I can detect oxidation like no other. Unfortunately, most imported beers tend to get oxidized through travel and improper handling. There is nothing worse than spending $15 on a 750ml bottle of a Belgian beer only to find it oxidized.
To add, I also love Wibiers. Ommegang Witte is probably one of my favorites.
I used to be rather partial to Matilda Bay's Redback, but I've not seen it around for a while.
I have a couple of Hoffbraus in the fridge as of yesterday - the direct result of dropping in at one of the more interesting bottle shops here and discovering that an old mate is the assistant manager...