Speaker for NAD C320BEE

Dear Audiogoners,
I have recently come to the hobby. My setup now is,

NAD C320BEE integrated amp (50 wpc)
NAD C521BEE CD player
Acoustic Energy Aegis 1 monitor speakers
Velodyne powered sub (80 watts?--it was $300 at the mall in 2000)

I'm looking to spend no more than $600 (new or used) to upgrade speakers. I would like a good all-around speaker--jazz, folk, rock, classical. The Aegis 1s are very good for some things (folk-rock, jazz), but not so kind to thicker music (e.g., Soundgarden). I am just starting to look around. So far have considering PSB (new, maybe Alpha T) or maybe Totem (used Rainmaker). Any suggestions greatly appreciated. In particular,
-Can I get new for $600 better than what I have now?
-monitor versus floorstanding given budget and amp?
-Is my sub worthy of pairing with good (c. $1,000 new) monitors?

Thanks!