His solo stuff is a long way away from the Chilis in terms of styles. Most of his material is about capturing a moment, the playing doesn't have to be flashy even though he is a great musician and the sound of his work ranges from DIY to full-blown production.
It really depends what you like I guess, if you like a bit of a DIY approach then I absolutely love "To Record Water Only for Ten Days" which is recorded on an 8-track.
Shadows Collide With People is probably as good a place to start as any, nice range to the songs and Frusciante sings brilliantly, Flea and Chad Smith play on most the songs too.
Curtains is a wonderful acoustic album.
Everything he's done has merit to be honest.