Just in case you're interested in how much louder (all things equal) your 200 watt amp will be compared to my 50 watt or dave's 100 watt, the equation is as follows:
10 log (watts A/watts B)
You do the more powerful amp as A and the less powerful B...
So, your amp vs dave's would mean
10 log (200/100) = 10 log 2 = 10 x 0.3 = 3dB
Now, 3 dB is the smallest difference in volume the average human ear can detect, and then only if they are heard side by side - in a gig situation nobody would be able to tell you were louder than anyone else due to cab dynamics and different speakers. Just so you know, you could get a bigger increase in volume by just changing the speaker out for something more sensitive (is that the word?)
Okay, so in comparison to my Screamer (which is $%&#ing loud - never been past 6 on the volume) you would be:
10 log 4 = 6dB louder
This is a bigger volume difference, but still not even twice as loud as my amp. 5dB is a sort of volume difference that people might notice in a gig situation, when not necessarily at the same time they may think "ah, he's a bit louder than the guy before" but still not enough to make people think "wooooaaah that guy is loud!"
The point I'm trying to make here is that you shouldn't get the 200 watt amp because of its power, as it will really not make that much of a difference in any situation (except it will have higher headroom, and take much longer to reach breakup - usually a bad thing). You would be much better off picking your amp based on its tonal qualities rather than the fact it's 200 watts - if you prefer the tone of KT88s then get those, but if you would actually rather the sound of EL34s then that would be your better bet as the extra power translates to very little volume difference overall.
You'd be better off investing in a more efficient set of speakers and a decent cab if you want more physical volume :drink:
sidenote: Hey Ben, I'm doing my audiologist impression again - twice in as many days :lol:
