I dunno if I agree with that. A lot of the 100 watters are high-gainers- a lot of the tone is in the preamp, and the high wattage is there for headroom, as (in my experience) power tube overdrive (or too much, anyway) just muddies things up, which you don't want when you're playing with high gain.
Plus I mean 10 watts is really, really loud too. You're not cranking that in a low volume situation either.
EDIT: Don't get me wrong, even with Engls they sound better turned up, but the kind of volume you have to get them to before they start sounding really good is not *that* loud... certainly a lot lower than a 10, or even 5, watter cranked would be.
EDIT #2: And I'm not saying you're doing this (you're not), but don't get me started on people who recommend vintage-voiced amps which are a lower wattage over a high-gain, high-wattage amp for people who need high gain :lol: