As Demonx suggested, get yourself a full drill set. Better yet, get a full metric (1mm - 13mm) and full imperial sets (1/64 - 1/2). Far cheaper in the long run than buying singles. If you're going to get any single drill bits, save your cash for brad point drills as you need them.
The router bits I find myself using the most frequently are inverted 1/2" diameter flush trim bits with 19mm and 28mm lengths (good for pickup cavities, neck pockets, trem cavities, control cavities, smaller template work etc), regular and inverted 3/4" diamter flush trimming bits with 38mm length (good for body outlines and larger template work), and a 38mm long 1/4" straight bit (perfect for Allparts trussrods, control wire channels, pickup cavities when used with a pattern ring on the router etc).
Also nice to have is a small set of forstner bits, good for removing excess timber prior to routing, or counter-boring neck screw ferrules and output jacks and the like.
Straight away there's about $300 worth of bits before you get started though.