Best bargain integrated amp?


I'm in the market for a new integrated amp. I currently own a Cambridge Audio 640A, but am begining to notice its short commings. I'm looking for a more refined amp with more power. I listen to mostly rock, jazz, acoustic guitar stuff: Leo Kottke, Nick Drake etc. in that order.

I would like to go second hand and spend no more than $700.00, and I guess my question is will I notice a considerable improvement sound quality with a second hand amp of this price?

I'm interested in the Odyssey Audio Cyclops but have yet to find it used. What other units should I consider?

My system:
Speakers: Acoustic Energy Aelite 2
CDP: ShengYa CD-s10 (tube)
Interconnects: Kimber Kable Timbre
Speaker Cables: PS Audio X-Stream Plus

Thanks for the help.
catt3
I own several amps and a standout at your price range would be the Audio Refinement Complete integrated amp. about 45 watts. I am surprised it has not been recommended up till now on this thread.
Check out Consonance I just bought an A120 Hybrid, great amp. There is a A120 SS for sale for $500 in the classifieds!
One of the most under-rated int-amps: Kavent/Vincent/Sheng Ya line of products. As a bonus, you also get defeatable tone controls
The cambridge is a good little amp. I used to have a Cambridge A500 5 years ago when I first got into hifi.

If you could spend a little more ($800) you can get a used Blue Circle CS. It's very musical and will sound awesome with you type of music. I love mine. It's a steal and a deal. Read some of the reviews on it. I think its worth saving for.

www.bluecircle.com

Happy listening,
Bought a NAD C352 recently (80 watts a side) to replace an 11 year old NAD 310 (20 watts a side)...spent under $500 new and huge bang for the buck..not much on looks but competes with much costlier pieces.