Best sounding op-amp

I have a stock Music-Hall CD-25 that I'm planning on doing some 'easy' tweaks on. One of tweaks I had in mind was changing the op-amps. It currently has a pair of Burr-Brown OPA2134PA's, but I was curious if anyone had any experience/suggestions on other op-amps that might produce a little 'warmer' sound. Possibly considering one of the Analog Devices op-amps like the AD823 or AD827. Any feedback or recommendations would be appreciated.

Op-amps do vary a lot in sound, particularly because of the power delivery on-die and on-package. Some parts are power starved from the get-go and need a lot of decoupling capacitance very close. Others are designed well for power delivery and need very little decoupling cap. These tend to be more dynamic and clean-sounding. OPA627 is my personal favorite. Packaging also has a big effect.
I'm currently using AD8620 on my Marantz 67SE and love it.
I also upgraded the clock board too.
After done much research, I found the AD8620 has the best spec.
Thanks for everyone's input... I'm leaning towards trying out the AD8620... does anyone know the difference between the AD8620-AR and AD8620-BR? The BR version is about double the price.

If op amps influence sound as much as people are saying, then op amps are being used in circuits where they don't belong. The headphone amp cited by Chillysalsa is probably a prime example. Op amps, even "good" ones are a lot cheaper than circuitry implemented with discrete transistors, so I suppose that widespread use is inevitable. Tubes anyone?
Here is the link to the product date sheet: