I would recommend going with a LCD because the plasma's are slowly becoming outdated and the initial advantages of plasma over LCD are dying.

I would recommend buying samsung or sony.
Samsung had the highest sales of LCD's last year.
Sony bravia with the bravia 2 engine is pretty good but is slightly more expensive.
I would recommend not going with LG as the prices are cheap but it doesnt have as much quality as samsung or sony has.

For samsung the official showrooms in qatar is techno blue.
For sony the official showroom in qatar is modern home.
Both have multiple branches.