Both of these will be great, both are pretty good brands. I personally would go for the Sceptre since it's ten inches bigger for about the same price. It has an 8ms response time which is pretty good for a TV this large.
Alternatively you could get a 1080p capable computer monitor for probably half the price. Lots of 24"+ monitors are 1080p.
As to graphics, size shouldn't have any effect, only resolution. So make sure your PC is strong enough to output at 1080p. PS3 definitely is.
