I suspect you may be disappointed by WSS - I love the 'look' of the period but a careful study arrived at the conclusion that it was a tactical bore. Sieges generally mattered more than the battles. And no one really won, the whole thing sort of just petered out. But it sure tempted the heck out of me for a long time.
Now, SYW - and stick with 15 mm because you can get so much more onto the table - gives you an entire planet to set games on, Europe, North America, India, the Caribbean, at the least. And it is tactically superior. Plus you get to field as many nations as you like within the bounds of reason - and those bounds are much wider here (way wider than the Boxer Rebellion by miles). See above for some good reasons - plus the arrival of horse artillery. And it is the 'gentlemanly' war (at least in Europe). And then there is Clive in India. No matter how long you live, no matter how much money you have, I cannot imagine exhausting this period. As to Eureka, sure they are nice figures and it is a great company to deal with but rather limited as to nations involved, pretty much you are limited to the eastern European theater by their figures. That is not all bad if you want the biggest and most notable battles (excluding the native monstrosities in India).
18th century gaming is just the coolest, though, so you can't go wrong. I have French Indian War and American War of Independence (and pirates in the earliest and latest part of the century - though way more Hollywood than historical!).