I didn't like the WLP011 European Ale yeast - used it twice and both times had a distinct off smell/flavor. It wasn't unpleasant, but it didn't exactly contribute anything to the beer. Both brews were pretty clean amber ales, and I think I narrowed the flavor down to the yeast because one batch was a small extract batch and one was a large all grain with completely different equipment. If I had to describe it, it was a papery smell and a slightly oxidized flavor. I'm almost certain oxidation was not an issue with these brews, and I haven't had a similar flavor in any other beer.
I REALLY liked the WLP002 English Ale yeast, though - clean, very flocculant. It almost acts like a fining agent because it so readily drops out of suspension. No problems with attenuation.
I wanted to use the WLP410 Belgian Wit II in my White Christmas brew, but all I could find was WLP400 Belgian Wit. I'm enjoying that one quite a bit at the moment. It's just now coming into its prime, and the flavors are really starting to blend well. I think the fruity esters produced by the Wit yeast will compliment a fruit addition, so WLP400 or WLP410 is my vote.