My most interesting was a Belgian Strong Golden-ish based on Poperings Hommelbier I've had the beer exactly once but it was so good and different, I wanted a clone. I got some good advice from a Dutch homebrewer on the NB board and ended up with a very tasty beer. I need to track down the inspiration beer again and see how I did.
My favorite beer was an Imperial Stout, which I think is the best beer I've ever made. I used a ton of roasted malt and Wyeast's Imperial Blend, which was a Private Collection release and I think that made the beer. It's bitter and roasty, with just a hint of tartness to it. I've had a few people tell me I should enter it in a competition, but that would mean less for me