I shut my computer off every night unless I am downloading a huge file, defragging, full system malware scans, video conversions, benchmarks, auditing, etc or need to charge both my phone and mp3 player, since my usb-to-ac is only one usb port on it, I unfortunately have to keep it on the comp all night (yes it's a waste but I need those items everywhere I go).
A lot of my time consuming maintenance software tools I run while I sleep, then reboot, then power down before going to work.
The issue with power downs/ups being hard on hardware is no issue if you buy quality parts. Like ASUS' newer mobos that have the 8+2 design step the voltage down so gradually that it's not "hard" on the system at all.
My computer is almost 7 yrs old (Athlon64 3500+, ASUS A8VE-Deluxe) and I have turned it on and powered it down literally every day. Still works like a sherman tank. Only thing that has died in it so far is one WD HDD I got the click of death two months ago but the drive was 9yrs old (funny, my 250gb maxtor that's 11yrs old is still running full speed.)
That issue really stopped being relivant 10 years ago, it was mainly for 286/386 systems. Hardware is much more efficient nowadays.