There are, fundamentally, two types of speakers used to amplify guitars. One is the type such as the Celestion Classic 30 (or "greenback", or Jensens, or Eminence "British", etc.etc), which are designed to add speaker distortion at some point a little less than their rated max. The others are more hi-fi, PA-type speakers that are designed to evade speaker distortion up to their ratings, which typically exceed 150w. If you like that blatty, farty, classic AC/DC,/Stones tone and aren't too worried about pristine tones, the Celestion 30's are a great choice. If you want a little more headroom, but still "want to rock" a Celestion 75 is a better bet. Many, many other guitarists like to use really clean high-power-rated PA speakers and let the amplifier (+pedals!) take care of all the distortion - they really are two different sounds. Good examples of this tone are early Santana with his JBL's or Duane Allman with his Altec/Lansings.
I'd say probably half the big-name guitarists out there nowadays are running the multiple amp setups pioneered by Steve Morse and Eric Johnson. Typically, you'd run a Marshall-type amp into Celestions, set to midrange to take care of the overdrive, and a Fender-type amp to pick up the clean highs and lows into JBL's, Black Widows, Eminence PA speakers or such. FWIW Santana (and Bonamassa) are running
four amps.....
Johnson creeps by with only three these days.
When I heard early Santana & Allman, I immediately chose to run with the PA speakers - I have a pair of Black Widows for big jobs, and an Eminence Beta-12A for littler stuff.
It's ALWAYS easy to add more distortion, but impossible to take it out..... :headbang1: