From the lack of information in the OP I will give you a generic response.
I much prefer plasma as I find the colors much more accurate and a better picture. So I would recommend plasma over LCD. This comes down to preference though, and there are plenty of good LCD's that approach plasma territory in colors (Sony XBR's, Sammy 71/81 series, etc) but are expensive. From your $1200 budget I would look at a 42 inch plasma (you might be able to pick up a 50 inch if you look hard enough). LCD's in that range will put you at the low to mid 40 inch screen size depending on brand/quality.
I like the Kuro's personally (Pioneer, plasma) and the 4280 can be found for not too much more then that $1200 (~$1400 most likely). Second would be at Panny plasma (don't recall pricing and dont know current pricing but IIRC 50 inch 75u was in this range). After that I would go to LCD's and most likely the Sharp Aquos.
Without more info I cannot help much more then this.