i'll second the votes for Incubus and 311. they are both two of my all time favorite bands who have steadily gone downhill with each album.
great albums:
incubus s.c.i.e.n.c.e.
incubus make yourself
311 grassroots
311 transistor
good albums:
incubus morning view
311 evolver
god awful craptastic albums:
incubus light grenades
311 uplifter
311 universal pulse