Of course I want two monitors for editing but I can't afford two Dell 24" LCDs just yet. So, one 24" with the following specs or two 20-inchers?

I'm on Vegas 7.0 (not installed yet because I have to buy a new computer as well) and will be editing HDV --> SD DVD.

From the Dell website:

E207WFP 20-inch Widescreen Flat Panel LCD
$246
1680x1050

UltraSharp 2407WFP Wide-Screen Black Flat Panel
$679
1920x1200

Are the 20-inchers a waste of time for HDV work?