Hi Ray,
This is just a FWIW, but I limped along for decades with a very small set of bits, occasionally buying special purpose bits needed for various projects. I've always done my own auto, home, electronics, etc maintenance, and I've wasted a lot of time that way.
Not long after I started my -7, I discovered that Harbor Freight offers this:
http://www.harborfreight.com/115-pc-titanium-nitride-coated-m2-high-speed-steel-drill-bit-set-61543.html
I've had that set for over a decade, and they stood up well drilling aluminum, until I started using the bits on really tough stuff like stainless and hardened steel, and for other 'odd jobs' around the house & hangar/shop.
Several years ago, I bought this set:
http://www.harborfreight.com/115-pc-cobalt-drill-bit-set-61886.html
I haven't used them a lot, but they do seem like pretty decent bits for the money.
I mention them because, especially with the less expensive set, you'll have any size you're likely to need for not much more money than buying ones & twos of specific bits.
For the highly repetitive jobs (#30 & #40, for instance), it's worthwhile to get a handful of quality bits from a reputable supplier, of course.
The inexpensive sets of 'step bits' from HF also do a decent job in aluminum sheet, and a tolerable job for those rare cases where you need a big hole in stainless (firewall, for instance).
Charlie