This might be better asked in OT, but resellerratings.com is your friend.
AT users recommend NewEgg.com most often and I've used them myself several times and like them (though I've never had to RMA anything, just get a replacement shipment for a box FedEX lost). Other recommendations are TCWO.com, MWave.com, and (a bit less unanimous) googlegear.com
For me it's worth the peace of mind to sometimes pay a couple of dollars more from NewEgg than from some garage operation that's undercutting them. NewEgg has about the smallest markup over dealer cost that you can have and still run a reputable company. Any lower prices and they have to be cutting out things like customer service.