If you’re looking for an alternative to a Record Pool try http://www.Just4djs.com They have all types of music – Remixes, Mashups, ReDrums, and Transitions all with Intros made for DJs. Plus no monthly subscription just pay as you go.
This is a great topic. I was actually going to ask this question today. I use beatport for Trance and house. I was going to ask because I want to start doing some mobile work and though itunes was my only option.
The quality is good everything is 320k MP3. Sign up for the news letter they do a lot of coupon discounts. Plus custom service is good if you have any questions or problems just email them, contact info is on the site.
I mostly use Itunes and Amazon for my regular music, but for anything like game remixes (I plan to play at a gaming convention) I go to a website called http://www.ocremix.org. All the remixes are actually free there.