Please, stop trying to sell me the Windows 8 UI for PC - it just doesn't work. MS should have had two modes - computer / touch device - and done both properly instead of the hybrid mess they've ended up with.
I've worked with multiple devices and OSs over the years and this has got to be the least thought-out and worst tested UI change I've had to deal with in a very long while.
You know I'm a bit torn on it now after a couple of weeks, I really put off installing Windows 8 because of all the negativity and now I'm plenty happy enough with it. Without altering settings or using mods, you can almost exclusively use desktop mode which is almost identical to Win7 on a PC and that I'm pretty happy with. If you were watching me use Windows 8, you would very rarely see any differences to me using Win7. The issues I have are basically how unintuitive it is, PC users get lost in Metro when they shouldn't really even be using it and it defaults to opening pics/music/PDFs etc in Metro apps when you're clearly in desktop mode and navigating Desktop Mode requires you to use shortcuts to be efficient. I cant imagine how long it would take a casual PC user to get to grips with when it's putting off experienced geeks who don't want to have to relearn a pointless UI change. So on the one hand I love it and would put it on all my desktops, but on the other hand I wouldn't really recommend it to anyone.
Once I'd rebooted everything behaved as normal and I sorted a backup and got the latest Windows Updates. Clearly the app had been jarring with other things....so my question do I reinstall the start button app, find a different start button app or do without?
I think you should try getting used to Windows 8, it's not that different really and quite nice when you're used to it, honest.

Just stay in Desktop Mode as much as possible, make sure your files are associated with desktop programs not metro apps, pin anything you use regularly to the task bar so you can launch it in 1 click and start becoming a shortcut ninja.
Launching an app: Hit Windows Key and just start typing the name of it, then click app once its shortlisted (exactly the same as Win7)
Getting out of Metro UI back to desktop: Windows Key + D
Admin Menu (improved version of old start menu): Windows Key + X
There's plenty more shortcuts, but those are really all you need. If anything seems annoying or clunky, there's usually a better way of doing it, its just finding the time to figure it out.