I dont know how they wouldnt be, unless it was a really old 640*480 one or something. THe native resolution on most LCDs (or CRTs, for that matter) is higher than HD standard.
Great link computerhakk! i work in retail selling this sort of thing and that article explains things really well to LCD n00b's. All LCD-TV's i sell at work are 1366x768 res wich will take most high def signals.
That was interesting that link that computerhakk provided while it pointed out the top to bottom resolution as 720 lines there was no mention of left - right resolution in lines,
For example while the top to bottom resolution is fixed on say a TV, VHS & S-VHS players/recorders. the left - right resolution in lines very from one to another on the three appliances given above.
(The visable top to bottom lines on standard TV 625 lines system is 585)
near the bottom the last picture, "Original source is on top, video representation is on bottom. The red and white dashes along the top denote the pixel positions."
take this comment near the top of the page While all (NTSC) TV sets and program material (broadcasts, tapes, disks, etc.) use the same 525 scan lines, the advertised resolution (240, 425, 500, etc.) refers to the horizontal resolution which is the number of side by side dots that can be reproduced within any one scan line.
I would say (with a guess) the horizontal resolution is 240 would be for standard VHS 425 would be for standard Television 500 would be for Super VHS tape recorder.