Old system thinking of changing

I have an old system nearly 20 years old, Marantz 63SE CD, Arcam Alpha 3 amp and Mission Cyrus speakers, I'm generally happy with the sound just wonder if the Marantz 6004cd and amp would be much better? If I get the Marantz 6004 which is about £470 what sort of speakers should I consider, budget would be about £400 although could go to £600 if worth it. A few facts, room is about 16 x 11 feet, music is fairly wide late 50s jazz (Davis, Coltrane, Pepper etc), 70s rock (Little Feat, Van Morrison, Dylan, Who), Celtic (Altan), Female vocals.