I have a 19" sony cpd-g420s crt that uses about 200w of power and defiantly puts out some heat, certainly much more than almost any lcd panel and it need no special cooling other than giving the vents enough space .
Heck my 37" HDTV only pulls maybe 230watts so I really don't think you need to add special cooling to a regular computer monitor unless it is super hot in your room in which case you need A/C not just a fan for the monitor.