David, this is the first transition that I don't fully understand. I have been around since the 68000 day or rather the beginning. From what I can tell, you wont need to buy new apps.
Spoiled is correct. You won't have to change any software except maybe the OS (The current version is optimized for the Power PC platform). They are working on making OSX run on the Intel Platform which should mean that it should be stable. From what I am seeing, Apple is really trying to encourage development on that platform.
BTW, Spoiled. I recall the 680x0 days. I have used the 68030 Mac SEs IIcx, and IIfx in my Mac Infancy.
I had an original Mac, IIse, Imagewriter I and II, Color Classic, Quadra 660 and 840 AV(those were really ahead of their time), Quadra 950?, the first beige G3(two of those), a host of various portables/laptops and the very first Super Drive equipped G4 733. A portable is once again in my near future.
I use Firefox as my browser so I see everything you do. I have a work PC laptop, so at first I compared everything and nothing looks different from a web standpoint. Now apple does have their own internet browser called "Safari" and with it I found it didn't show some webpages the same as a PC and that is what prompted me to get Firefox.
As for the desktop, you don't have 50 icons plaguing the screen like you tend to have with a PC. Mac's are very clean and simplified. Installing and uninstalling a program is as simple as drag and drop.
But to answer your question, nothing is different on when viewing this website on my Mac.
From what I can tell, you wont need to buy new apps.