Guys, guys, guys...
Clean tone is C-L-E-A-N!!!!
"Slight breakup", "Crunch", etc., are NOT CLEAN tones!
My preferred clean tone comes from a 6L6 amp. I like the tighter bottom and the extended highs of the 6L6 over the more compressed tones of a smaller EL84 amp. I like big, powerful amps. But those little bottles do have their charms.
In all honesty, it comes down to what YOU like. Whether it's Nile Rodgers' rhythm clicks, Don Rich's ballsy Tele-pickin' or Andy Summer's riffing, there are many ways to produce a clean tone that sounds good.
The real key, as always, is finding the tone that SERVES THE SONG. Do that, and you'll be a winner every time.
Bill