Numero 2: Dont care, they can die in hole
Hmph. See if I ever talk you guys up again.
To the OP, it's honestly hard to answer your question in a way that'll be meaningful to you, I think. Me, I love Alliance-side RP (and Imfernal's completely irrational and heartbreaking hatred notwithstanding, I also love cross-faction RP). But what I love in RP may not be what you love in RP. Imfernal's suggestion to roll here before you server transfer is a good one. I don't think you can really get a feel for the community until you've been in it a little while.
Our tavern night (that is, the Devilclaw Outlaws') is in Duskwood at the Scarlet Raven most Tuesday evenings. Feel free to drop by! If you come on Alliance, we may even offer you a drink and be not entirely unfriendly. :D (OOC we're pretty friendly; IC we're a little leery of strangers, due to the whole being outlaws thing.) If you come on Horde, we'll...probably leave you alone unless you start killing people. Except trolls -- some of our members might /purr at you if you're a troll (you know, the race, not the griefer). Or Mordrok, apparently, I'm not quite clear on the Mordrok thing. No promises.
I know House Blackstone has a tavern night as well (ohgod, I can't remember what night -- Wednesdays?), and their guild is more an organized House with a top-down structure, I think? Eowynn would be able to say more about it. And there's GnomeTech, who do a lot of social events including an annual prom, and a bunch of race-specific guilds like The Päck, Clan Battlehammer, Sentinels of the Blade -- this is just a little sample of the Ally-side RP guilds.
So, what are you looking for in an RP community?
P.S. For godssake don't join Dreadwaste Defilers. They're a bunch of meanies.
P.P.P.S. Except for Imfernal, whom I will never rescue from a hole.