I have a good set of 1/4", 3/8", and 1/2" rachets and sockets, the 3/8" get the most use. I used to use a lot of open-end/box end wrenches, but a little less than a year ago I got a set of ratcheting K.D open-end/box-end wrenchs (Pelican sells them, but not the set that I got, I wanted the ratcheting wrenches with the pivoting heads) they are awesome, one of the best tool purchases I've made.

A couple of the tools from the stock tool kit are really nice as well, the spark plug tool, the fan belt tool, even the screw drivers are decent. Occasionally some allen wrenches (extra-long), the swivel ended ones are nice too, and also a set of allen sockets. Fortunately most of the stuff on a 911 can be done with open-end/box-end wrenches, a couple of allen wrenches, and screw drivers.

These are what Wayne sells,

http://www.drivewerks.com/catalog/ShopCart/TOOL/POR_TOOL_CAT190-detail.htm

This is what I got, KD tools 9901, the flex head portion is Grrrrreat!
http://arizonatools.com/catalog/browse/3586-3595-2599-2744,3/detail/13878/

Excellent points, multimeter, good jack (actually even though they are pricey a Great Jack like the one that Wayne sells is really worth the cost once you get it), a 1" micrometer, vernier caliper, a good bleeder of your choice, apparently the Motive is the bleeder of choice, but I get by with my mityvac suction bleeder, Something that I really want but don't have yet is a parts cleaner, a good, clean bench to work on, a good creeper (they have some great, comfortable, low profile models around these days), i use knee pads from when I tiled my house when kneeling behind the car, a good light that you can position. a sturdy set of jack stands

My favorite tool? I have a credit card that works for most thing...if it is really big job I'll use a second one. I switched from using my checkbook because I needed more leverage...

H.G.P.
The thing about air tools is a mechanic can put in some long hours. Sometims 12 hours a day. Not only do you save time you save energy, YOURS. Also why bust your knuckles when air can break loose nuts quicker and painlessly.

Mike

Now why couldn't I find this thing when I replaced my front speakers???? I ended up using one of those bits (from another tool set) and a cheapo ratcheting wrench. Now I need to get this too!!