Originally Posted by rm -rf

Those kits have a lot of tools that you'll never use.

These will get you started: It's really all you need now.
The main one: A set of metric hex keys (the L shaped 6-sided tools), from 8mm to 1.5mm. I have one of the sets that's attached to a handle, where each key folds out. But I also use a loose set of the L shaped keys, since these fit into tighter spaces and I have more control over the tightening force.

Phillips screwdrivers, both #1 and #2 sizes, and a small flat blade screwdriver.
A wire cutter ("diagonal cutter") Mostly for cutting cables ties.
A pedal wrench to remove your pedals. (some pedals only use a long 8mm hex wrench--their axle doesn't have the flat sides that the wrench fits on.)
A spoke tool.
A chain tool to push out a pin when replacing the chain. I always use a Connex chain link on the new chain. It's tricky to get the pin pushed in correctly on a new 10 speed chain, and the Connex link is really easy.
Electrical tape.
Tire levers for changing tubes.
This--> A link to Park Tool's repair site: http://www.parktool.com/blog/repair-help

Also, needle nose pliers, and regular pliers are occasionally handy.

Later:
A repair stand makes a lot of jobs much easier.
A chain whip and cassette tool to match your cassette type.
A small torque wrench if you are tightening carbon components.
A bottom bracket tool to remove the crank axle bearings.