Nadia slows down in the middle...a LOT. Back in the day the fan subbers actually skipped a bunch of the "island episodes" because they are so boring and contribute little to the worth of the series. The ending is AMAZING though, so I recommend people stick with it. The movie though, is just garbage. You can skip that.
Lately I've been watching Space Brothers, which can been seen for free on Crunchy Roll. It's really good! For people who want something that isn't just pure shonen retred, check this out. The best show I've seen in a long time. It's a near future setting with two brothers that want to be astronauts. One already is, the other decides to go for it a bit latter in life after problems with his career.
Recently Gundam Unicorn 5 came out and things got pretty exciting with that show again, probably the best episode yet. The series has now been extended to 7 episodes total, so it will be finished in...2013. The only OVA I can think of that took longer to make this many episodes was Giant Robo: The Animation, and even then it wasn't actually planned that way, this is. I don't know of this series will turn out to be as good as GR, but it is pretty damned good.