Which World of Warcraft Private Server is right for me?

I'd like to play WoW again, but I'm not sure if I want to commit to paying for a subscription. I know I can get time cards and such, but first I'd just like to play for a bit to get re-acquainted with the game (I played for a year, but I had to quit.). My question is, which private server is best for me? I'd like to get as close as possible to the actual, pay-to-play game; my two criteria being a mid-to-high population as well as actual work to level (I hate it when servers just hand you the highest level and equipment on a silver platter.) Also, a small side-question, does the official World of Warcraft website offer a free game download, or is it bought like the discs? Please Help!