The three best sounding amps I've had, in no particular order:
Genz-Benz Shuttle (the 6.0 I used to have, and the 9.2 I have now) -- clean, powerful, and ridiculously light... the perfect amp for a gigging 59-year-old
Eden WT400 -- lovely uncoloured sound. The best live sound I've ever had was when I borrowed @Kiwi's old Ken Smith BSR 5 and played it through the Eden. They were made for each other.
Trace Elliot GP12SMX -- still my favourite preamp of all time.