if i had a plasma tv i'd bring as they do not take a great deal of space and they should have a variable voltage

i have no idea about prices really but would think it would be similar to the US, probably there a little cheaper, although someone else would be able to tell better

here's a couple of sites for some elctronics

http://www.modernhome.com.qa/modern/default.htm
http://www.jumboqatar.com/

I think both are a bit pricey

http://www.carrefourqatar.com/carrefourqatar/English/home-eng.htm
Like Walmart
http://www.luluhypermarket.com/
Arabic Walmart
Family Food Centre .. sells some
http://family.com.qa/

plus many many more