Thanks again, everyone. The reason I went for the 3TB Fusion Drive is for simplicity and storage capacity right out of the box - without any extras. I do still have to time to change the configuration if I'm convinced to do so. However, I'm very confident that the 128GB of SSD flash storage will work well for me on a daily basis.
Keep in mind that I'm currently using a mid-2012 MBP with a 2.9GHz i7 single core processor and only 16GB of memory. My daily chores consist of editing photos in Photoshop, running a web browser with 15-25 open tabs, email coming and going all day, and Pandora running for music. That's about it. More rarely I do some web editing and use FTP to transfer fairly small files.
I'm almost positive I'll be under that 128GB of flash storage most of the time. On very rare occasion I go through iPhoto - LOTS of photos - so I may run into issues there. However, it's very rare that I'm in there so if I see a "beachball", I'll be okay with it. Same goes for iMovie. Every so often I'll create a slideshow or edit a video I take with my smartphone and I imagine there may be an issue there. But I do this so rarely. It won't interfere with my daily activities.
Even so, if it became a more frequent exercise in the future - it'll have to be an improvement over what I'm working with now. I'm anxious to finally get a good screen so my photo edits will look great. I'll probably leave my old 27" Samsung screen for email duty as I'm currently always going back and forth between my browser and email...
I have a previous generation 3TB Time Capsule and I'll probably keep my current MBP hooked up as is other than removing some things I'll no longer need -- and I'll connect the new iMac to the same backup. As it stands now, I'm using about 1TB of the Time Capsule and figure I'll probably use about the same amount of space on the iMac - leaving me about 1TB of free space on the backup.
I feel pretty good about my backup situation. If something goes wrong with the Time Machine, I'll just go out and buy a new one that day, connect it to my computers, and back everything up again... Not sure what else there is. I just hope I get the iMac soon. My current MBP is constantly backing up 6GB to Time Machine and my computer crawls (choppy mouse arrow on the screen) driving me crazy. I don't know what the problem is but I've gone through a few steps I read about here and I never come to a resolution. No big deal. The new iMac will have a fresh start and should work as intended.
I wish there was a way to schedule Time Machine backups. I used to use an app for that but I'm stuck on El Capitan because I need to keep Dreamweaver CS3 working on this computer. So those apps no longer work. I have a feeling the hourly Time Machine backups won't be a problem on the newer, much more powerful iMac...
P.S. I love this site. The members here have always come through when I had an issue - either steering me in the right direction or providing the information I needed. It's a shame that some sites are so horrific with ads that I needed to install an AdBlocker. I felt bad last night after I realized I hadn't turned it off here. Of course, I have now. The ads here are non-obtrusive and I'm happy to support the site. I'd browsed a few hours with all the ads blocked. I think there should be a quick, simple message letting visitors know they can turn off their ad blocker here...