The set i use is (from precise bits)

• v90,v60,v45 isolation trace bits http://www.precisebits.com/products/carbidebits/scoreengrave.asp
• 0.008 0.015, 0.0313, 0.0625 and 0.125 stub ends (end mills) http://www.precisebits.com/products/carbidebits/precisebit-stub.asp
• 0.80 mm (note metric, all others are inches) router, which is the smallest they have at precisebits http://www.precisebits.com/products/carbidebits/fcrouter.asp

You can do just about any board with that set just about (outside of drill bits), which you'd want in a range. Typical sizes are 0.016 0.032, 0.036, 0.040, 0.125, you'll usually never have the right one you need, so design the board so you do or get lots. http://www.precisebits.com/products/carbidebits/drills.asp?tsPT=wire

I use the depth rings, but not the bushing, the ZrN coating says it lasts longer, but i have no data.

The bits don't last as long as you might think, so best to double up on everything, they're expensive too..

http://www.precisebits.com/applications/pcbtools.htm