Which amps for Monitor Audio Gold Reference 60's?

Hi All,

I am in the hunt for an amp for the Monitor Audio GR-60's. These are fairly bright so a bright amp will not do. Anyone who has got or has heard these speakers what recommendations can you give. Perhaps not specific makes but guidelines to start with such as:
- Solid state necessary or are tubes ok?
- Is a pre/power required or will a decent integrated work well?
- Do they need oodles of power or will a solid 50W of tube power or other Class A power do the trick (they seem to be fairly efficient).

My main concern is that I want something not too birght, but not too lacklustre or loose - it must be able to control the sound, especially the bass, without contributing to harshness.

Thanks,
X