Camalot Z4 Cam by Black Diamond — The Z4's are my favorite cams on the market. Since they are only available for the small sizes (0 to 0.75), I would recommend buying Z4's in all the sizes available, then get C4's for the larger sized cams.
For full-rack quantities, you'll want two of each for size 0.3 to size 3. Only one cam needed for sizes 0, 0.1, 0.2, and 4.
Camalot C4 Cam by Black Diamond — C4's are the standard by which all other cams are measured and, in my opinion, the best value for your money. While I do prefer the Z4's for the sizes they're available, I also own C4's in all the sizes and they perform great.
My recommendation for building a full rack of cams to tackle nearly any climb: get one of each of sizes 0, 0.1, 0.2, and 4; get two of each in sizes 0.3 to 3.
Black Diamond LiteWire Rackpack by Black Diamond — You'll need a racking carabiner for each cam that you own, color matched. Buying the BD Rackpack can save a little money but each of these colors is also available in singles.
Wired Stopper Set by Black Diamond — Gotta have a rack of passive protection! Some call these nuts, some call them stoppers. I recommend just carrying one set of these to supplement your active protection pieces while trad climbing.
Pro-Key Nut Tool + Leash by Wild Country — If you carry stoppers, you need to also carry a nut tool. I like this Wild Country nut tool for the leash that prevents accidental drops.
C.A.M.P. Tricam EVO - Set of 4 by Camp — Some people love tricams, some hate them--personally, I love them! Can be used as either passive or active protection and can be very useful in the right situation. I recommend carrying a set of these while trad climbing to compliment your cams and nuts.
Metolius Multi-loop Contour Gear Sling Multi-Colored by Metolius — This sling is how I rack my cams for trad climbing. Some people rack cams directly onto the gear loops their harness; I prefer to use this gear sling so that I can quickly rack up and easily swap leads. It also allows me to keep my harness gear organized as normal.
Miniwire Alpine Quickdraw 3 Pack by Black Diamond — You'll need alpine draws to connect your protection to your rope while leading. In some cases, you'll want to extend your draw to prevent rope drag and reduce abrasion. This is one of the reasons we use alpine draws in lieu of of quickdraws.
An alpine draw typically consists of a 60cm sewn sling and two non-locking carabiners. However, for extending past roofs, you'll want a couple double-length (120cm) alpine draws.
You can either buy a sling and two non-lockers to make your own alpine draw or buy a pre-made alpine draw, usually in sets of three or four. The pre-made option will save you a few dollars per draw but you can't customize your color scheme. I prefer black carabiners for my draws so that I don't confuse them with the racking carabiners for the cams.
C4 Camalot Set by Black Diamond — Buying cams in sets offers a better deal than buying strictly as singles.
Black Diamond LiteWire Carabiner Black by Black Diamond — For building your own alpine draws, use two non-locking carabiners like these and add a sewn sling. <div>I recommend using black carabiners for your alpine draws so they don't conflict with the colors of your racking carabiners.</div><div>This LiteWire series is a little bigger and better for larger hands.</div>
Sling - 11 mm by Metolius — For making your own alpine draws, I recommend using a 60cm sling and adding two non-locking carabiners.
You'll want mostly 60cm alpine draws to trad lead, but you should add a couple 120cm double-length alpine draws for extending past roofs.
Black Diamond MiniWire Carabiner Black by Black Diamond — For building your own alpine draws, use two non-locking carabiners like these and add a sewn sling.
I recommend using black carabiners for your alpine draws so they don't conflict with the colors of your racking carabiners.
This MiniWire series is a little smaller and better for smaller hands.
Black Diamond MiniWire Rackpack - Package of 6 by Black Diamond — Color coordinated to rack your cams--for leaders with smaller hands.
The MiniWire racking carabiners are my recommendation for those with smaller hands. I personally prefer the hand feel of the LiteWire non-locking carabiners to rack my cams but my hands are on the larger side.
Black Diamond Crag 40 Pack Gray S/M by Black Diamond — Great climbing pack for trad days. Plenty of space for your rack and gear, plus the ability to carry your rope on the outside of your pack. Super durable and comfortable to wear.