My contrary view is that no one else at least no one unfamiliar with your style and preferences can help you out here. The strongest opening in your case (and mine since we are only about 100 rating pts apart) is the one that works the best for you, at our level it's ridiculous to believe that 1.e4 is better or worse than 1.d4, it all depends on what you like to play ie attack or defense, open, semi-open or closed games etc. And you can easily find 1.e4 and 1.d4 openings that will suit your style and preferences. Even though I always play 1.e4 you might want to concentrate on 1.d4 as I believe many amateurs like myself are much more familiar with and partial to 1.e4 openings. Or you could play both and be more open-minded than I am, at least so far.
What opening do you think is the strongest for white to play?

Even though I'm a total patzer, I agree with NimzoRoy. First, if there was a "best" first move, then every GM would stick with that move every time. They don't, so that alone should tell you something.
But more to the point, even if 1. b4 were objectively the very best first move bar none, it still requires that moves 2 through the end of the game be played correctly. Given that it is unlikely for someone rated below the titled ranks to do that with any consistency, focusing on whcih is best as oppossed to which leads to positions you find most playable misses the point of the opening.

Well, to decide on a "best opening for white" is kinda unreasonable. I put this into my engine to see what it would say, and it preferred the Ruy Lopez, and then the queens gambit. NOW, it is not too be said that the Ruy Lopez is a lot better than the Queens Gambit. I personally love the Queens gambit and yet I hate the ruy (I used to love it at one point). It is all depending on what style you play. If you are agressive, try the ponziani (yes, the ponziani, if anyone says that its a bad opening, slap them LOL) and if you are a positional player, try queens gambit or catalan. Overall, some would say that both of these are good openings, but why not play something less commmon like c4. People who play c4 actually tend to win more than e4/d4 players. (Thats a fun fact). Also, the difference in my engine analysis was only like .03 (I did this a while ago, so I don't remember the exact difference). So it doesn't really matter what you play, as long as it isn't the barnes opening (1. f3) lol.
Good luck with your quest to find the perfect opening ;)

I've heard that 1.d4 is better for lower-rated amateurs like myself because it leads to more positional (and thus more predictable) play. Once you reach 2000+ it is best to switch to 1.e4, as you are tactically sharp enough to be rewarded for deeper knowledge down opening lines like ruy lopez, sicilian najdorf/dragon, etc.
Personally, i think e4 opening and the queens gambit is the strongest but i prefer the queens in tournament play. Do you have a contrary view?