If we are focusing on 2000's mainstream rap here is my hit list from back in the day:
(Definitely missing a lot but kidn of threw it together.)
Andre Nickatina- My all time favorite rapper. Most people just know his single "Ayo for Yayo" but he has a long list of dope albums. "Conversation with a Devil" is his classic album for sure.
Another Bay Area classic is Mac Dre. He is most known for his Thizzle stuff but his more lyrical songs are awesome and hilarious:
Afro Man: Speaking of hilarious rap songs, if you were in High School back in 2005 this was the best shit lol
Baby Boy da Prince- Def a One Hit Wonder but "The Way I Live" is what we all bumped in 2006-2007:
Then in the late 2000's the rap game realized it got to clean, too refined. It needed to get grimy and thus the Dirty South Movement began:
Ying Yang Twins:
Lil John basically held together the whole Dirty South Movement. Maybe not the best lyricist but makes up for it for sheer over the top spectacle:
About this time EDM started to become popular as well. Pitbull was really the one that brought together Latin Influences, Crunk and House Music. A lot of people hated him but he had some dope tracks to throw on at parties:
Around the end of the 2000s people could only take so much grimy Dirty South Crunk and that is when T-Pain came on the scene. Say what you want about T-Pain but this was revolutionary when it came out and he actually used auto-tune as an art instead of a crutch. Most modern rap basically is just a copy of the sound that T-Pain and Lil Wayne did in the late 2000s:
Also shoutout to Tech N9ne. He was always kind of on the fringes of the mainstream during this time and would get thrown on every now and again at parties. Some people hated his style but he could spit verses like no one else. I remember back around 2007 he played at Rock the Bells at Red Rocks and basically stole the show.