The best art for striking would be American Kickboxing IMO.
Joe Lewis (the founder) not only was the World Heavyweight Kickboxing champion, but has also trained with world class Muay Thai trainers, Muay Boran (Burmese kickboxing) trainers, western boxing trainers (such as Angelo Dundee, Dus D’mato), world champion boxers (such as Ali, Sugar Ray Robinson, to name a few, etc…) and of course Bruce Lee.
If you can find a school run by one of Joe’s black belts that would be the place I would go to learn striking. You’ll learn everything that Muay Thai, Muay Boran, and western boxing have to offer, and it’s all combined into a complete striking art.
As far as grappling goes, I’d agree that you can’t go wrong with wrestling and JJ. But really what you need is to be well rounded.
You need to be able to take your opponent down, and to be able to defend takedowns. You need to be able to achieve, maintain, and escape various positions on the ground. You need to be able to apply and defend against submissions/finishing holds/locks/chokes. And you need to be able to blend your grappling skills with your striking skills on the ground and in the clinch.
What ever combination of grappling arts best does that for you, go for it.