I have a Dell Inspiron 8200, which runs EQ and other games just fine. 2Ghz, 512mb ram, 64mb GeForce4. It's alot slower than the desktop, but I can run with all models on, without serious lag even in raid situations.
You could probably get away wih less, important elements are:
a) Video Card - you need a good, Dx9 capable card. (64MB+, ATI or Nvidia)
b) RAM - 512 is the minimum you want. Laptop hard drives are always slower than desktop ones, so more than ussual you want to aovid swapping. More ram the better, I'd suggest a Gig.
c) Decent Processor. (Much of EQ's display is done on the CPU, so the better processor, the faster EQ will run)