(1) Going from a 100 watt amp to a 200 watt amp is an upgrade. Going from a 100 watt am to a 150 watt amp is not.
-Assuming all else the same, going from 100W to 200W would give you 3 dB more clean power, which is noticable, and may mean the difference between distortion and pure audio at listening levels. In reality, though, when you change amps, so many different factors come into play, such as if one is over/under rated and how they handle diferent impedences. Sometimes the 50wpc amp can be better than the 200 wpc amp. Power rating's aren't ALL THAT. (Thus I disagree with your statement)
(2) Going separates is alaways an upgrade.
-I disagree, as I believe that my Denon AVR-5800 is better than some of the lower-end separates out there. Although, the truly elite items are all separates, and you won't find any bargain basement separates like you do for receivers (ie. $90 DD/dts 5.1 receivers).
(3) Going from consumer brands (Pioneer, Onkyo, Yamaha, Sony, Wharfedale, Mission, etc.) to boutique brands (Rotel, Aragon, Sunfire, Krell, Martin Logan, Sonus Faber, etc.) is always an upgrade.
-Look at the answer above - the same can apply here.
(4) Going from stereo to multi-channel is an upgrade.
-If done properly it CAN be an upgrade, but I rather have stereo at the moment for audio.
(5) Going from 5.1 to 7.1 and up is an upgrade.
-Depends on how well it's done. If done right, it is more immersive, in my opinion.
(6) Going for DPL to DPLIIx and other formats is an upgrade
-Yes, especially when you get away from those nasty analog surround formats (DPL, DPLII) and go to digital discrete surround.
(7) Going from HTIB to anywhere is an upgrade
-Now I want to say that some where, out there, there is a HTIB that actually sounds good, but I can't find an example. While it is possible that there is, I doubt it. I agree here, unless you're talking about going BOSE, which is baaaad.
(8) Going from B-O-S-E satellites to any other speakers is an upgrade
-If it isn't a $50 set of multimedia speakers, yes.
(9) Going from a hardware cables to exotic cables is an upgrade (???)
-I disagree.
(10) Going from Solid State to Tubes is an upgrade (???)
-I definately disagree. Although this may sound nicer, due to harmonics that the tube amps apply, it is less accurate.
(11) Going from Digital to Analog is an upgrade (???)
-I disagree, although some analog equipment is BETTER than some digital equipment.