The odd thing about guitarists and speakers is that generally
they don't like high fidelity offerings. Cheaply made, poorly
designed speakers give guitarists the sounds they like. Look
at any company's guitar speakers, and compare them to their pro
audio brothers within even the same company; peaky frequency
response, low power handling capability, inadequate power
handling and cooling capability, dinky voice coils, high
percentage of distortion artifacts, etc.
These speakers are chosen precisely because these flaws seem
to complement the electric guitar, especially as they are driven
towards their limits, for guitarists who choose to play with
some edge of distortion. I have used cheap Gorilla speakers,
Eminence, and others that give me the same characteristics as
some Celestions do.
There are those who play cleanly that like a more precise
speaker, and there are some rockers like Steve Morse who use
higher fidelity speakers as well (JBLs in his case, I believe).
For guitar amps, I think the combined rating of the speakers
should at least match the rating of the power amp, unless you
are going for a certain sound and have spares lying about. A
lot depends on the player, and how they set their amp.
Me, I like to play on the edge of distortion, and both of
my cabinets are now loaded with Celestions. I got 'em cheap...
---Michael (of APP)...