If the TV is a modern flat-panel LCD, you shouldn't have to worry about sparks igniting dust.  Old CRTs had a lot of voltage that could arc and ignite dust in the past.  If you are putting a plasma display in there (Mr Fancy Pants...) then there is high-voltage in there.

I'm typing this on my shop computer and it is 96F in here now.  The computer itself is in a closet in the house with a long HDMI cable to this wall-mounted monitor.  It works fine (my webcam, however, shuts off audio once it gets over 102F... regrettably, I know!)

Covering the TV to protect from dust likely won't work well and may not be good for it.  Dust will find its way behind the cover and drive you nuts.  Leave the screen as is.  If you want to protect against projectiles, put the screen away from the TV a bit for access to clean the screen.

I rarely clean my screen out here.  Your turning won't generate dust.  Wipe the screen down with some eyeglass cleaner as most have anti-static chemicals added so it won't attract dust.

Just no pay channels in the shop; too distracting. 

i was planing on buying a small cheap flat screen (probably lcd) and a free to air  satalite recever. nothing to stimuulating.
i wouldnt be doing anything major  with the tv on but it would be nice to be out there  organising or thinking  about a project ect while watch  a match etc.
there is a shocking amount of dust sanding on the lathe and it is very hard to extract.