i would not suggest getting a TN panel monitor larger than 24" unless you want to risk seeing color shifting around the edges.
led backlighting will definitely you money when it comes to power savings but realize the two risks: first panels with edgelit (all of them at this point in time) led backlighting you have a higher chance of backlight bleeding. also on cheaper units (non professional) models wleds might be used which reproduce white as a blue-white tint which i have heard can be adjusted out in the settings.
the fastest response time monitors are TN. this panel type is also the only one capable of 120hz at this time. however realize that you do not need 1-2ms response times. it is doubtful that you would see ghosting even on a panel with 14ms response times.
tn: cheap, fast rt, 60hz or 120hz, bad viewing angle/color shift
va: not too familiar on this type...
e-ips (6bit): same color quality as prior but very wide viewing angle (178/179 deg), mid priced, slower response time
p-ips, s-ips, h-ips (8bit): best color accuracy, wide viewing angle, expensive, slower response time.
for that budget i would try to look at e-ips (6bit) panels from dell, asus or viewsonic unless you are dead-set on 3d/120hz.