there appears to be a wide range of issues when either trying to restore or transfer files backed up to time machine
TimeMachine doesn't have a clean install option. It's why I don't use it and prefer bootable clones instead as they are direct accessible in case I do just want grab files and change permissions to the new account, dumping the rest.
With timed clones on seperate hardware, makes it easier to revert from a previous OS X version or optimize and defragment your boot hard drive for better performance using a clone, booting from it and reverse cloning.
Make a bootable clone of your boot drive
Most commonly used backup methods
Why is my computer slow?
How to safely defrag a Mac's hard drive
I'm primarily worried about restoring my email (googlemail), My 500gb itunes library and my significant library of photographs in Aperture.
To fresh install, you need to backup files manually to external drive (not timemachine), then wipe everything and set the machine up like brand new, with new user accounts, preferably with the same drive name (MacintoshHD) user account names, then return files to each account and do a #6 Repair Users Permissions on the files.
..Step by Step to fix your Mac
iTunes shouldn't be much of a problem, provided you tag the songs in the playlist with the playlist names (attaches to the song files themselves) and use the same drive name and user account name on the fresh install so the pathnames in the itunes database matches where your files are at.
Aperture shouldn't be much of a problem for the same reason, as long as you copy the contents of your home folders direclty back into the new account folders of the same name, again to match the pathames where your files are at.
Gmail has a online website, so your emails are there, make sure you have the password. They should redownload to your machine once you set up mail in the new account (with the same name)
Local email files on the existing system will be erased with the fresh install method because they are likely seure and hidden in the invisible User/Library folder, which doesn't get restored with the fresh install method. (but will with TimeMachine restores as it copies everything)
Follow the A2 method here for a fresh install of OS X, your just targeting the existing MacintoshHD partition, a full drive wipe isn't necessary.
Reset your Mac
You also might want to read this also, it can be used for the fresh install method.
How to revert OS X back from Mavericks