I love the Hellsing TV show and like the direction they took it in. Ultimate is pretty cool too, but in my opinion all it really has over the show is a higher budget. I think given what they had, the show actually has better art and animation considering. It's just a cooler show with much better talent behind it. Buuuut, I know I'm in the minority, "has no Nazi vampires," yaddayadda. Despite being a fan of the manga, that weird Incognito guy is way more interesting to me.
And yeah, there's also the music too, of course, which helps add to the stylish awesomeness of the show.
URP, NOPE, I'M JUST KIDDING, HURP DURP DURP DURP
Of course I'm not fucking kidding, sass-mouth. ;)