I could do diskless if it weren't for ~4GB of email and a quota that doesn't fit anywhere near that. Also have a ~1G email influx every 6 months before I prune the useless crap back down to 4GB. That and having the email local on SSD makes searching through it SOOO much faster.
I customize the crap out of both Linux and Windows... For Linux, I have a list of packages that must be installed for my system and then I just transfer my home directory over. fvwm, vpnc, vnc, mrxvt, rainlendar, pidgin, volwheel, systrayx, TB, FF, VirtualBox, vim, audacious, LibreOffice. That's just for work... then personal includes KiCad and necessary compilers. W7 goes in a VM, mostly for IE and corp crap that doesn't have a Linux equivalent.
Windows... I have a theme I load up, shove the taskbar on the left edge of the screen and my apps get pinned and a couple scripts onto a small toolbar for sleeping the PC and monitor. All Snap, AHK, Cygwin, EAC, FF, ImgBurn, IrfanView, Jumplist Extender, KiCad, Launchy, LibreOffice, PuTTY, Rainlendar, Sketchup, SoundSwitch, Steam, TB, FF, VNC, UltraMon, Vim, VirtualBox, WinAmp, WinSCP, XManager, Zoom Player. Also a few AHK scripts to deal with my hotkeys and wallpaper.