What's the major difference between these two since you can hook both up to a PC.
But you can buy bigger LCD TV screen size wise.
TVs atm are capped at 1080p (99% of them anyways), while most monitors 30+ have higher than 1080p resolutions. SO yes you can buy a 46in TV for much less than 46 inch monitor (do 46 monitor even exist?) but the resolution compared to size will be crap. Also most TVs in the sub $1.5k range are TN panels while msot $500+ monitors are IPS based, which will give you a significantly better picture. And lastly most TVs lack the quick refresh rate of modern non crap monitors.
You can buy a good 25inch 1080p TN based monitor for under $200 which will be good for msot games. Good luck finding a sub 32inch TV thats 1080p, they are all 720p.
Now I am not saying that playing a big screen TV is a bad thing, some ppl do like the whole "playing from your couch" experience, and of course movies are great. But smaller, higher res monitors will look much better, just for the pixel density/size if nothing else.
This will depend on how you like to view things, bigger monitor will still maintain 16:9 or a 16:10 widescreen aspect ratio. Eyefinity , unless you are going to use at least 4 monitors will be very very wide screen (32:10 or so).
Both are cool, but they are not the same (in short bigger monitor =/= eyefinity stacked across)