I love 19 bg. I've built a number of characters for it and find it to be a highly competitive bracket; as such I'll offer you what I can on this.
There are several pieces of 'universal' eqiupment for each build:
First of all no matter what class you take, take engineering. Aside from winning the +15 hat for fishing in STV, its really the only way to get a headpiece worth anything (with good stam to boot).
Every class can be very potent in this range. The minimum of skills means the 'learn to play' creed becomes highly important as it can make or break even a twink-character. So learn to play the class you want to learn.
For weapons: unless you can readily get a BOP/BOE, your best bet might be to get your 40 wsg marks and get your faction's weapon. It's about as good as anything else.
For necklaces: Really your only viable option is going to be the WSG faction-specific item. It's +2stam and +6agi. There's not much equipment to choose from in this bracket.
For rings: If you're on alliance go for this beauty:
http://www.thottbot.com/?i=2287 .. it's a quest you can finish at a low level and the ring will work for 19bg. The faction wsg reward rings are pretty sweet too. I also prefer a blood ring for the stamina.
On to gear: For mail wearers (paladins and warriors) there is alot of good gear to make you into a combo dps/tank machine. Contrary to the previous person I will say that you want to go agi/stam for paladins and warriors. This is because it's so easy to get a high crit rate and in the case of warriors you also can get that nice +5% crit off fury spec. It's not out of line to see a 20% crit rate at this level on a fury warriorr with the right gear.
So what is the right gear? Well from my experience there are two builds for a warrior:
tanking/dps
crit/dps
The dfifference being that one is all mail for the armor and the other is a mix of leather/mail.
Then of course you have the option of going 2 hander or 1 hander + shield. I prefer 1 hander plus shield because of the extra armor, stats, and +stam enchants which can be done on the shield versus just 2h alone.
Realistically it's impossible to list every possible combination so I'm going to just list what I have for my 19 fury warrior (alliance) who is possibly my favorite class to play 19 bg in.
weapon: cruel barb (bop off vc) +damage enchant
shield: redbeard crest +stam ench
finger 1: seal of wrynn
finger 2: legionnaire's ring
neck: sentinel's medallion
trinket: insignia of the alliance (had this from before the patch)
legs; chausses of westfall (quest reward for doing dm/vc) +armor
feet: silver-linked footguards +stam ench
hands: thorbia's gauntlets:
head: flying tiger goggles
the rest is filled in with lvl 19 greens with agi/stam or agi/str on them. I run about 1200 hp unbuffed with a 12% crit rate. Now if I'd have twinked him earlier I'd have gone and run WC for the cloak (high drop rate +6 agi) and the cobrahn's grasp. Unfortunately I'm sitting at 3 bars right now before I level to 20 so that's not gonna happen.
The most important attribute though I've seen is stamina for any class. It makes a huge impact.
My girlfriend as a specc'd pally which absolutely dominates this bracket. Similar gear but she went far enough to get the +100 libram enchants and sits around 1380 hp unbuffed. With devotion aura she pulls about 1800 armor which is even higher than mine and about a 10% crit rate. She also uses the exploding sheep to excellent effect (engineering tree) as well, something I don't see too often. It does 150 damage, aoe. At this bracket that's pretty rough, often comprising 35-50% of a non-twink's hp. Plus it is homing
I've found my cloth wearers are significantly less dependant on gear and much more so on play style. You want high +int and +stam. This can be done with greens from level 15-19 since armor is less critical. Thottbot is your friend for finding what blues there are thogh really the ones available are less than stellar.
Lastly for a poor man's buff you can take a higher level char and have them put a heavy armor kit on your low level armor. This will give you +24 armor instead of +16 until you can afford either a libram or +stam enchant.