I believe Double EXP is still working fine.
My Pally has benefitted greatly in the last two weeks from all the server merges and double experience. He has gone from level 38 to level 43.81% in that brief period of time.
Last night, I spent most of my time doing easy quests in Feerott and managed to make about 50% exp in about 2 hours. An easy quest was yielding about 3% exp and you could see the exp move when I was killing groups of 3 down arrow mobs.
Also, discovery exp is just sick. Buy a chameleon totem and run around zones, carefully avoiding see through invis mobs. Desert of Flames yielded 20% exp in about 30 minutes and lots of fun.
Runnyeye is another place for awesome exp now. If you can get a good group and head for the heriocs and named, you could easily walk out with a crapload of exp and the occaisional master drop and uber loot.