Look, you aren't making alot of sense to me? Why did you upgrade to 10.6? What is the scanner? Is it on a list of non-supported scanners? What is special about it? Is it worth downgrading to 10.5 again and wait for a scanner of the type you need to be available.. it is very easy to downgrade. New plain scanners are very inexpensive, but most folks now purchase them as part of an All-in-one printer and these are so inexpensive that they are worth upgrading on a frequent basis (once each 3 to 4 years)- I didn't have any issue with iTunes when I upgraded but we did have an issue with the Apple TV and this is resolved by upgrading the iTunes and the Apple TV needs a tweek too. You have discovered this. I just don't understand... you say you have been around the block but then you say you jumped into 10.6 and are now shocked that some things need new drivers and such. You obviously didn't go through the fiasco with 10.4 which wasn't even stable until 10.4.3 and had to be reinstalled if you upgraded to 10.4.1 because it corrupted the spelling check database.
10.5 upgrades went much smoother and I can't remember a single one that waiting to see and hear the howl go up from the users about some new unforseen bug... I just think we got spoiled with 10.5
10.6 has been pretty good so far. HP Printers all had issues right at the first and it was a complete battle on getting updated drivers in because the list supported was too small.. but now.. they have every one I need which is alot.
There is no way to run a scsi scanner any more and this has been the case for about 4 years so thats not your issue.
If you don't want hassles at all.. don't upgrade immediately.. wait for the release of 10.X.2 or 10.X.3. This is when most of the unusual stuff is cleaned up. This is why Microsoft does a period of months of a public beta to get these hard to create bugs to pop. Apple has much less in the way of issues and the early adopters find all of this crap and complain loudly and then in the 2nd or 3rd maintenance update it is mostly all cleared. Anyone who has been using a mac for a while understands this.
I simply said I had a piece of hardware that worked and when I upgraded it no longer worked. For me, the hassle and the time to get it to work again is weighed against the "benefits" brought by the new OS. I NEVER upgrade immediately, usually read if there are problems, and thus avoid them. I got bitten anyway.
Sorry, but I don't buy the crap line: "Well, just buy a new scanner. Its cheap." Microsoft tried that line when Vista destroyed functionality with peripherals and got hammered (rightly so). I don't need to buy a new peripheral each time I upgrade, and if I'm expected to, then drop the price of the computer by about 90%.
My BIGGEST beef was with the AppleTV/iTunes fiasco. There is absolutely NO excuse for Apple to screw up in that regard. They own the hardware, they own the OS. If they can't get the two to talk together without a problem, then they have serious quality control issues.