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
Sold my Cambridge Audio integrated to buy the Melody/Onix SP3. is is just great - I really anjoy the difference.

It has lots of authority for a tube unit, but if bass slam is what you are after, you might need to stick with transistors or perhaps a hybrid unit like one of the Xindaks that has been appearing on eBay.
Portal Audio Panache designed by Nelson pass (?) or Musical Fidelity X-150.
Audio Aero Prima is a hybrid integrated. It contains 1 tube in the preamp section.
The SS amp portion puts out 40 watts. It has more than enough power and base for dynamic music such as rock.
It is quite a bit better than my Rotel seperates that preceded it.
There is a Mk I listed now for $680.
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!