There's a post on the boards right now for a medical first aid kit; that's my set of choices.
Meds, I like Tylan (injectable w/3 cc syringes and 20 gauge needles), LS50, I keep Sulmet on hand always. I dislike Terramycin.
Well heck, here's my general list:
Corid AND Sulmet (one for babies, one for adults)
Probios dispersible powder or Acidophilis capsules
A bottle of organic apple cider vinegar
A couple of bottles of babyfood applesauce
LS50 antibiotics
Penicillin G Procaine in the fridge
Cuticle scissors (buy good ones - you'll use these to cut off tiny bits of flesh or trim small feathers gently around wounds)
regular scissors or "penny cutting" scissors (great for bandages and splints)
Hydrogen peroxide - a very large bottle
Betadine - a small bottle will do.
Neosporin without pain killer
terramycin ophthalmic ointment (from the feedstore - keep inside)
a spray on like Alucoat or Alushield (horse section, feedstore)
q-tips
duct tape
popsicle sticks (for application of meds, or for splints for baby chicks)
Paint-stirring sticks (bigger splints)
wrapping gauze
non-stick gauze pads
Maxi-pads (they're clean and absorb a lot of blood from wounds - not joking)
Vet-wrap a plenty! (Buy it from the feedstore - it's cheaper than the pharmacy and it comes in colors to try to make things feel more positive)
Suture material (cat or dog size - see online or at better feedstores)
Hemostats (for suturing or for plucking maggots or feathers)
tweezers
alcohol - a large container
a clean cheap white sheet (to make slings from or cover wounds if necessary)
A GOOD blood clotter like Clotisol - vet recommended and non toxic even in the beak, unlike styptics. One small bottle lasts years.
paper towels - you can throw them away, and they're clean.
non-latex gloves in bulk - a box. Sometimes you need to wear two pair.
a news paper (absorbant and makes clean up easier if you have to flush wounds)
Several 3 cc syringes with 22-25 gauge needles
16 gauge needles to replace on the 3 cc syringes if using penicillin
2 10-30cc syringes without needles for flushing wounds
A toolbox to keep all non-refrigerated items in
Superglue (emergency suture)
Barn supplies:
permethrin dust ("poultry dust")
ivermectin (wormer and delouser) - I prefer drop-on generic.
wazine (piperazine 17% solution - first time wormer)
a smock or something to wear when handling ill birds
a fold up cheap plastic table on which you can treat wounds and then hose off and disinfect
a clip on lamp in case you need direct lighting
an extension cord
a couple of glass jars in which to make iodine solution or keep warm water
a 5 gallon bucket to throw stuff away in that can be disinfected.
BOOKS: There are a number of them. Storey is good, Damerow's book is good. But honestly some of the best information is online, googled. I should make a list of favorite links. hmmmm
By the way - this ungodly list of goodies is best built up a piece or two at a time. 
