[Andomar]

Recently I tried a lot of new addons just to see what they were doing. These two were really great and have earned a permanent place in my Addons directory:

AutoRepair - Addons - Curse
Automatically repairs your gear when you visit a repair vendor

Crap Away! - Addons - Curse
Automatically vendors grey items

[Petninja]

Alternatively, you could try Smooth Durability and TekJunkSeller. Those are what I use. I imagine a junk seller is a junk seller is a junk seller, but the armor repair one has some nice features.

[Niian]

Funnily enough if you use Auctioneer it comes with an automatic vendor option for greys and anything you add to a list.
Can't remember the exact name of the module, but it's "easy" something.

[Blue]

I've been using Crap Away for quite a while. It's been very stable and I like not having to give a second thought to clicking on all the white's and grays to get rid of them, every time I turn in a quest, or go to a vendor.

Autorepair seems less useful, as it's only one click, anyway. But then, it probably doesn't have much of a resource footprint, so whatever floats yer boat, I guess!

I also use Bag Sort, and I love it...all I have to do is type /bagsort, and it does it's thing, quickly and well. /banksort works, too, for, yes, one's bank.