Good Speakers for Low Watts

I am putting together my first system. I am a Jazz Bassist and listen to around 2-3 hours of music a day. I am not after a super hi-fi system,as the watts and pricerange indicate,just somthing better than the day to day mini system stuff out there. I am thinking of getting an older musical fidelity amp A-1 20w or B-1 35w. I want clear sound with definition. Loudness is socondary. I like to hear seperation of instruments. Can anyone sugesst a monitor/book shelf speaker pairing for 200-300 used?