Building a well-rounded set of bits
For ordinary casual woodworking and household maintenance, almost any drill bit is sufficient. Fancy coatings make little difference for light-duty use. "Split points" can make drilling in exactly the right place easier on difficult materials; I haven't noticed much difference when drilling wood.

The kind of bit, in larger sizes, will make more difference -- above half an inch you start having to choose between spade bits (inexpensive), hole saws (mid priced, cleaner cuts), and Forstner-and-similar (more expensive, clean holes, can do some things neither of the others can,  but drill sliwer than hole saws; they're more often used on drill presses), or a few other less-common variations in the theme. (I own bits in all three of those categories, for different tasks). 

I haven't used impact drivers enough to have opinions on those yet.