What sort of rack should you build for heading outside?
As point of reference I pull up what Yuji Hirayama and I used to climb The Nose In A Day, (NIAD) in 2002 and "flush out" a rack from there so that you can get up most any climb.
"For our 2002 ascent we carried one #3 camalot, one #2, two #1s, one.75, one .5, and doubles below that,(some of our smaller cams were Metolious tricams). 6 nuts, one cam hook, one etrier, 17 quick draws, 18 free biners, 6 long runners, a Gri gri, a couple lockers, Petzl jugs, and a set of JJs, (jugging loops)."
If you are only free climbing you can ignore the etriers, jugs, and JJs.
Here's the things I'd add to the above rack for anyone who just wants to have a reasonable rack to take on just about any trad climb.:
A set of tiny offset Nuts, and 6 more .5 to 1 inch regular nuts.
A #.5, #.75, #1, and #2 Link-Cam from Omega Pacific (These didn't exist in 2002)
Two Cordelets, theses are 5 to 7 mm cords in 18 to 22 ft in length, great for anchors on trees, gear, LARGE boulders, or bolts.
Offset Metolious tricams are really nice for pin scares or any flaring placement. Get the middle four of the six sizes they make.
Get a rappel device, I would most recommend a Petzl Reverso as it has Top Belay lock off capabilities that a regular stitch plate device does not have. -the Reverso only costs a small bit more than a standard stitch plate type device.
If you know you are going to be doing wide cracks then buy another #2 camalot, another #3 and two #4s. There are very few cracks that are continuously wide and require more than this, on the occasion that they do, I recommend asking to borrow from friends. (ask me if you need)
Lastly if you know a crack you are headed up is notorious for a certain size for a long distance than add to this rack accordingly or borrow. For the people who really like to have plenty of everything and then some get more in the .5 to 1.5 inch range than I've listed.