I'm a firm believer in buy now, save later.
I bought a David Clark at the start of my PPL (I'm about to finish it!) and have since purchased Lightspeed Zulu 2. The active noise canceling does make a big difference.
I could've saved myself a bunch of cash just buying the Zulu's right out of the gate, although I found the DC's on eBay for £50! I keep them around for PAX now.
Bottom line, if you can afford it, do it.