I'm not big on their first album (I know it's my avatar, but that's mostly just for the album art). It's raw, but not as catchy and well-produced as Freaky Styley and Uplift Mofo. Plus, it's sorely missing their heart and soul on the guitar.
My RHCP Album rankings:
1. Blood Sugar Sex Magik - love every song
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2. Freakey Styley - funktastic
3. Mother's Milk - better production and this album might be higher
4. The Uplift Mofo Party Plan - a smoother sounding version of the self-titled
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5. One Hot Minute - all about Flea
6. Red Hot Chili Peppers - raw, lacks some of the catchy-ness of the next couple albums
7. Californication - has some classic tracks like 'Around the World' and 'Get on Top', but also demonstrates what is to follow
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8. Stadium Arcadium - yuck! (I like maybe five songs)
9. By The Way - double yuck! (I like maybe three songs)