1. Zath - Favorite is probably U. calycifida, because it includes the Lovecraftian cultivars, whose mythos I am a huge fan of. Learning about them from B. Rice's articles helped stoke the fires of my CP obsession in the first place.
2. SFLguy - Utricularia Delphinioides - although usually purple, it can turn a deep blue that I believe is unique to Utricularia (biloba comes fairly close though I believe), and quite simply, it's beautiful
3. charlie - My favorite is U. purpurea I love seeing pictures of them in mass flower. That's why I "need" biloba
4. PitcherPlantr - My favorite would probably be Utricularia westonii because of the brilliant red bladders it produces just above the surface. It is quite a unique species.
5. hcarlton - U. regia, as of currently. The multiple colors and unique split petal shape are gorgeous; second might be U. volubilis, for the rich color and shape.
6. rjhaway - My favorite would probably be U. quelchii because I like the bright red flowers.
7. ErrorEN - U. arnhemica. Why? Because above ground traps!
8. Clue - U. multifida, not just because of the amazing in situ shots of fields of flowers, but because Polypompholyx is just so much fun to say.
9. patrickntd - U. foliosa. Although its flower is not attractive, I like its well organised and dense traps arrangement as well as its vigorous growth.
10. gnathaniel -- U. pubescens mostly because I love the growth habit, which reminds me of the ripples from raindrops hitting a pond. Hard to choose a favorite, though, Utricularia includes so many beautiful plants I'd like to grow someday.
I tried to fix the list to put hcarlton and Clue back into the order, hope my meddling is alright with everyone. Thanks for the great giveaway, Tanukimo!