How Much Money Should I Be Putting Into a Budget?

I've been at a point where I've been saving and investing about 40 to 50% of my pre tax income. So instead of focusing on being more frugal this year or investing more, I really want to figure out areas where I can spend more for the most return. It's not a big amount that I have, you know, to add here somewhere around 10 to 15,000 disposable income to do that. But I was wondering what broad categories should I be looking at.