I'm not even going to vote I'm so torn.
Generally, if I had the opportunity, I'd chose to watch the show in English. English dubbing has gotten good enough to where 3 out of 5 series today either match the original track, or do an even better job. I also prefer to watch in English most of the time for the reasons Deadfire listed. It's just more natural for me to watch a show in my native language. That said, if I've watched a series subbed, I'll usually stick to the subs. I think with a lot of people, whichever way they watch it first is the way they prefer. Watching anime in Japanese is also just cool. There's a certain charm that comes along with listening to a series in its native language. You guys know what I'm talking about.
I'm also a VA fanatic through and through, so that holds a lot of weight in deciding whether I watch a show dubbed in English or subbed in Japanese. If a Japanese voice actor that I love (like Masaya Onosaka, Romi Paku, or Shinichiro Miki) is cast in a series, I'll HAVE to listen to it subbed. The same goes with English voice actors. Any series that casts Blum, Mary Elizabeth McGlynn, or Liam O'Brian to name a few, earns an automatic English viewing. I'm also intensly interested whenever a show I've seen subbed is dubbed. I love seeing who-will-play-who and comparing line deliveries and styles of voices (hence the Naruto and Bleach dub threads I've created). Because of this, I'll often do what Yukimura said and watch it subbed first, then in English with the subtitles on.
I know exactly what you're talking about (Goddamn, does EVERY ADV dub have to pair up Monica Rial and Chris Patton???), but I don't think that aspect of dubbing makes it any worse. In fact a lot of the time, I have fun trying to recognize voice actors from different series. Hearing the same actor in different roles is really cool, except when as you said, they sound...exactly the same. And are cast in every other series. The exception to this is the God that is Steve Blum - who is probably the most prolific anime voice actor out there, but has such talent and vocal range that it doesn't even matter when you hear him 5 times a night on Adult Swim. Has anyone else heard him do video game stuff like in Psychonauts? He's amazing.The earlier dub casts in the late 90's and early 2000's were a lot better than what we have now. Pick up anything from then and you get diverse casts who really put a lot of effort into their acting. You get natural sounding emotions, and even attempts to mimic the original cast, thus getting the same effect the voice director on the Japanese track was going for. Then, for whatever reason, someone hit a wall. You'd hear the exact same cast in everything.
Of course I couldn't agree more. Some notable dubs I've seen just recently: Elfen Leid, Naruto, Fullmetal Alchemist, Final Fantasy: Advent Children, Fruits Basket, Eureka Seven, Ghost in the Shell: Stand Alone Complex, and Paranoia Agent. I could go on, but all of these did an awesome job and had a unique cast from one another. They also used both accomplished voice actors with good range as well as some new talents, showing that the cast reusing isn't as extreme as you say it is.But the voicework is improving at a slow rate
Another interesting point is that a lot of people claim to prefer subs because they say it's "original". In the end though, aren't most anime series based on manga? Aren't the lines just coming from written text? Any dub in any language is just that actor's portrayal of those written lines. Any American actor resembling the Japanese actors just seems like a nod to a good performance to me...and not a necessity for a good dub. People complained that Ed Elric sounded too different from Romi Paku and hated the FMA dub, even though the actor (Vic Mignogna) fit the role perfectly and in my opinion gave the best performance of his career. Again, I think preference is usually based on which language the show was watched in first.