Here's a brief listing of things rogue based off the top of my head. Remember, that as a leatherworker, you'll also want to check out LW rewards!
Aldor - Epic sword at exalted, also atleast a blue ring that you can buy, and of course shoulder enchants at honored and revered.
Scryer - Epic dagger at exalted - the fastest of the 3 epic rep daggers; also a pair of pants at revered (you'll likely already have these replaced by the time you would get them), and of course the shoulder enchants.
You should grind exalted with one of the above factions when you hit 70. You'll eventually want to have the shoulder enchant.
For heroic keys you'll need revered with: honor hold, lower city, the shatar (sp?), cen expedition, and keepers of time. I've found that honor hold/thral is the most boring as a rogue. Do yourself a favor and try to get in as many instance groups as possible while you're leveling in that area. You'll get rep and hopefully be able to make revered without having to come back and farm shattered halls (which has relatively little good rogue loot and sucks a fat one). Cen exp is similar... again run instances! And turn in your unidentified plant parts early as you can't do it after honored! It's not a bad idea to do all your faction specific quests in that zone first so you can collect some plant parts, turn them in, then do the quests from Cen exp! For the other 3 factions, keepers of time specificially, it doesn't really matter... you'll get most of your rep from instances. Lower city and shatar (again sp?) have some quests, but not nearly as many as honor hold and cen exp.
Cen Exp - Revered gets you the helm glyph (34ap/16hit) which you IMHO should be atleast able to purchase. There is also a chest piece at honored that's fairly decent while leveling.
KoT - Exalted dagger, the slowest/hardest hitting of the rep daggers. Also a decent PvP trinket at exalted(with a wierd PvE effect) if you need some extra stam and resiliance for PvP.
Consortium - dagger at exalted (nerfed next patch but still good - only stats were nerfed a bit), gun at revered with decent stats.
I know there's a nice bow that you can get in thral with exalted, and I think there's a gun for aliance in honor hold. If the stats are the same, that's a good piece too.