I'm a huge fans of tracks where a rapper flows over the beat from a track by another rapper. These aren't always found on cds, so you gotta download them. Here is a list of some that I've heard off the top of my head. Kanye West - Gimme the light freestyle Kanye West - Bonnie and Clyde freestyle Kanye West feat Common - Milkshake freestyle Fabolous - Da Rockwilder freestyle Mike Jones feat Paul Wall - Get it on the floor freestyle Jay-Z - Bump, bump, bump, freestyle Jay-Z - Stand Up freestyle Lil Flip - Lose yourself freestyle G-Unit - Right Thurr freestyle I wanna find some more, so if you know of any please post them. Edit: Lets include diss tracks in this thread. For example, "Bump Heads" where Shady and G-Unit go after Ja Rule. List those too.
Theres to many to mention by my boy JR Writer, he got some nice freestyles, 5 Minutes of Crack is one of them, hes a great freestyle MC.