A bit of background reading tells me the 990, as Tarquinh says, is apparently rather good, however, at nearly £1000, that's off the radar for me. Not so the HK6550, or HK680 from a few years back however. Apparently superb and very highly rated in their day. Still actively sought out in some quarters too. I've also seen a Meridian 551.
Just finding my current set-up is starting to niggle a little; mostly being as neutral as it is (well, I think so), so very revealing with great recordings (a good thing!), but just revealing (read unforgiving) of poorer recordings too. Hence, I think, why I'm delighted with well mastered discs and it sounds great, but less than overwhelmed with a lot of other material.