If it's only for exhibitions, you may be better off renting one. How many exhibitions do you do a year? Also, if you rent, they'll have to deliver/collect the very heavy screen!!
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€1,999.95 from Richersounds.ie
       
Excellent value 42" screen from Daewoo. Typical selling price is €3300. Save over €1000 !! Not a brilliant plasma, but good value for money. Ideally suited to businesses etc as it's not great at handling large motion sequences.