US is undoubtably superior, we spend more on the military of the other 9 countries usually listed in the top 10 combined. Our technological advantage is so great and speed and range so far reaching, no other military can stand against it. Some have argued China could simply based on sheer numbers, even though lacking in technical prowess can make up for it in sheer bodies, in fact some list China #1 for this reason... I don't buy that, but do believe war with China is likely inevitable and will happen eventually. Russia, its military is in decline still has a lot of relatively high tech weaponry relative to the rest of the worl and a sizeable military. Israel gets number 4, technologically sound, rapid, able to mobilize up to 1/2 a Million reserves nearly instantly, and ready to fight. I don't think any nation in that area of the world could stand up to a concerted attack by Isreal. Iraq has numbers, but its armor is ancient, troops poorly trained, and as we saw in 91, can be routed quickly with modern techniques and hardware. (same with most of the arab states). I would not advise israel fight every nation on its borders simultaneously, but I would bet on Isreal winning if it happened.
What about North Korea?